The five leprechauns don't seem persuaded by the group's arguments or suggestions, and begin cracking their knuckles with wide grins, almost as if they hoped it would come to conflict. The lead leprechaun gives his answer...

Your beet-syrup scheme we’ll ignore,
For honey’s the treat we adore!
You'll give us what’s ours,
Or we'll use our powers,
To take Polinella - and more!

Roll for initiative!

By shadows you leprechauns boast,
Yet you offer no welcome, no toasts;
Click your heels, flee the night,
Or be drowned in void-born light—
And wander forever as pale, hollow ghosts.

     To the lead leprechaun - thought is quicker than initiative? (lol)

Two of the five leprechauns remain where they are, blocking the road, while the other three move around to the sides of the group, apparently trying to flank them. All five wear evil grins, and are chuckling or muttering strange words like "Begorrah!" or "Gobshite!", while cracking their knuckles or rolling up their sleeves. There is no response from the leprechaun being warned by Mulligan's clever rhymes...

Suddenly, without warning, a small swarm of bees appears just beside Amidor, who attempts to disperse them with one waving leaf. An instant later, an object comes sailing out of the darkness and strikes Greginald, shattering. Shards of fine glass tinkle to the ground around the gnome as something thick, sweet and sticky oozes over him.

Greginald: Please make a DC 13 Dexterity saving throw, or become restrained in honey until the start of your next turn.

Seeing that this is going to turn violent, G'Reg ships out his spell book and prepared to fight. Only to be directly focused in honey and rooted to the spot. "Ah bollocks! What in the.... Uh Barria! Show me what you can do with that war hammer eh? Don't let them hit me!" With a plea of desperation the gnome casts a spell upon Barria and she, along with her items, clothes and weapons, grow to a large size towering over the leprechauns (+1d4 to all your melee damage output, plus advantage on all strength saves and checks)

Rowan just notices his lute is missing. As he looks around he fails to notice that the leprechauns have become violent until everyone else has already started moving.

     Mulligan takes a quick scan of the field of battle and tries to determine his prime target.  So far there is plenty of room between most of the combatants and he feels it would be difficult to attack sneakily for maximum effectiveness... unless he attacks the smallest combatants.  Retreating west a bit he moves into position to strike out at the bees attacking Amidor.

Psychic Blade vs Swarm of Bees:  8 to hit for 5 psychic damage
BA Psychic Blade vs Swam of Bees:  Nat 1 for 7 to hit for 7 psychic damage
     Sneak Attack: 8 additional damage if either of the above hit, which I do not think they do...

     Cursing in his head, Mulligan wonders what the hell he was doing swatting at bees....

((Inspiration gained from the Nat 1 on the attack roll...  AND I will immediately give it to Barria with the reminder that Inspiration is used as written in the 2014 PHB, namely prior to making an attack/saving/ability roll to give yourself advantage on that roll.))

Barria frowns as the leprechauns surround them and start to attack.  "Hey now!  Leave the bee alone!"  she is a bit surprised as they use what she thought would be precious honey to them as a weapon and sticks G'Reg where he stands.

As the wizard's power makes her grow, her mouth drops open and her eyes go wide, "What in Chauntea's name have you done to me?!" But she starts smiling as the implications dawn on her.  "You got it little man!  I'll just smack some sense in these naughty creatures!"

She moves around the group and heads towards Lorcan, making sure she is between him and G'Reg and pulls out the war hammer she had tied to her belt.  She tests the weight of it in her hands now that it has grown in size as well and her eyes sparkle with delight.  It's about this time that she feels the inspiration come from Mulligan and thinks, these fellas ain't too bad to be around after all.

Attack w/inspiration: 13, Damage: 4 + 4

The leprechaun threats already had him agitated and jumpy, then when Rowan realizes he can't find his lute, his emotions start to bubble up, with little sparks of energy popping along his skin and arms, but then when they throw a jar of honey, bees swarm Amidor, and suddenly Barria gets large, Rowan loses the last tenuous control of his emotions he did have.

A tangled, wild garden mass of flowers and thick twisting vines grows out from Rowan, spring up and filling all the ground within a 15' radius. Surprisingly, the vines and flowers move to the side when Rowan moves, and maybe more surprisingly, they don't impair the movement of any of his friends either. But the leprechauns find the vines cumbersome and slow going (all enemies have to treat the area within 15' of Rowan as difficult terrain).

Rowan then races forward, dancing over and through the vines until he gets to Padraig, his longsword already out and swing as he gets there, a two handed chop sweeping at the leprechaun.

Longsword - two handed - (11+6) = 17 to hit for (8+4+ 2 from rage) = 14 slashing damage.

Mulligan slips between the bodies and over beside the dandelion. As he does so, there is a strange "pshew" sound as a shimmering blade of pure energy extends out from each of the rogue's hands. He swings them through the dark air with a soft buzz, but the swarm of bees seems to simply bend and morph around the blades. Glister also comes over to help, trying to swat the bees away, and Amidor's rapier manages to make contact with a few of the insects, which drop to the ground buzzing angrily, but the rest sting at the valiant flower.

Rowan's emotions cause the ground around him to erupt in foliage, with vines and flowers bursting from the ground, and then vanishing just as suddenly as he moves away. The elf swings his sword at the leprechaun, but the blade passes right through the grinning fey like he was made of air! There is an amused chuckle from the oddly non-solid creature.

The gnomish magic washes over Barria, causing her to vibrate rapidly as she grows to ogre size. The ground shakes as the oversize dwarf goes thumping across the mountain path, her warhammer raised for the swing. But before she reaches the cheeky smiling leprechaun, she crashes into something, which almost causes her to fall head over heels. Her Warhammer instinctively swings downward to brace her fall... and thumps against something soft. There is an "OW!" from at Barria's feet, followed by a "Shite!" and then a scuffling as whoever or whatever Barria stomped on and then squashed with her hammer, tries to move away. The dwarf follows the movement though, (even as the leprechaun she had orginally been moving toward remains in place, smiling and chuckling), and in fact there is a small spray of dust, noticeable to all, where the invisible figure stops.

Meanwhile, Mulligan sees another leprechaun materialise out of thin air on the opposite side of Amidor. It grabs at Polinella, the dandelion's beloved companion, but luckily the large bumblebee queen buzzes out of his reach, causing the leprechaun to scowl and curse under his breath.

Another small vial of honey sails through the air and crashes to the ground beside Mulligan, missing him. However Barria and even Rowan notice the spot that the throw originated from, and spot the tip of a leprechaun's hat disappearing from view behind some rocks.

DESCRIPTION
The five leprechauns are all still grinning and chuckling, although Padraig has proved to be immune to Rowan's sword attacks, and indeed apparently incorporeal.
Figure 1 is visible to Barria and Rowan, but Hidden to others
Figure 2 is invisible, but the location is known to all.
And another leprechaun, identical to Padraig, has appeared beside Amidor.

EFFECTS
Barria is under the effects of the Enlarge spell
Greg is no longer restrained. He is concentrating on Enlarge.
Rowan is Raging (Wild Surge 7).

Rowan looks surprised for a moment as his blade swings harmlessly through the leprechaun then he smiles and laughs, thoroughly enjoying the encounter.

"It's like a fun house. Find the real ones," Rowan says, then he spots Barria. "Oh wow, you grew."

Rowan decides to bound back across the clearing to the invisible leprechaun that Barria bumped into. The vines and flowers flow across the space with him.

His exuberance gets the better of him and he swings his longsword wildly without any thought of defending himself in an effort to connect with the mostly hidden little creature.

Reckless Attack - Longsword - two handed - (15+6 adv from Reckless Attack negating dadv from invisible opponent) = 21 to hit for (7+4 + 2 from Rage) = 13 slashing

     Mulligan is still focused on the swarm of bees, perhaps more so after so embarrassingly missing them twice already!  In fact he barely even notices the fact the leprechaun don't seem to be where they seem to be or that Barria has reached new heights... (Perception check 3 argues that he is hyper-focused on the swarm...)  As such, he calls forth two new psychic blades and attacks once more!

Psychic Blade vs Swarm of Bees: Nat 1 for 7 to hit for 7 psychic damage (seriously??  again??)
BA Psychic Blade vs Swam of Bees:  (w/Adv from the Nat 1)  16 or 7 +6 for 22 to hit for 5 psychic damage
     Sneak Attack: 7 additional damage (12 total) as I assume the BA attack hits.

Barria's sights stay with the dusty creature she ran into and she turns to follow it.  She wonders what is going on for Rowan's blade to go straight through the other leprechaun, but shakes that thought away as this thing obviously is solid.

As she reaches #1, she takes another swing at it with her war hammer.

Attack: 20, Damage: 10

g'Reg tries to keep himself as well positioned as possible with Glister and Milligan acting as shields on one side and Barria on the other. He holds concentration and spots the invisible shuffling and dust kicking of whatever Barris is following. He takes a pot shot with a ray of frost changing the spell from his book and focussing on the general area in question. (18 to hit with disadvantage, 2 cold damage and speed of target reduced by 10ft) "Hells! Did I get it? Barria is it still there?"

Mulligan continues to swipe at the swarm of bees, gaining some satisfaction as more drop out of the air and lay stunned, twitching on the ground. With less of them now, Amidor seems less bothered by their stings, and stabs with his rapier at Polinella's assailant, scoring a masterful stroke. The leprechaun curses in pain and calls out:

I grabbed at the bee, but she ducked,
And this flowery knave has me mucked!
O lads, lend a hand,
Grab her now as we planned,
The queen must be ours ere we’re … fecked!

With that, another leprechaun materialises out of nowhere - this one with a noticeably large frying pan in one hand ... identical to Barria's frying pan in fact! The two leprechauns together have another grab at Polinella, but again she evades their attempts at capture. Meanwhile, another swarm of bees appears overhead and begins to engulf the embattled dandelion.

The elf acrobat's orange hair glows brighter until a shaft of bright light zaps out toward the two would-be kidnappers. Both leprechauns avoid the sudden beam of light, but stare at Glister with wide-eyed surprise.

Greginald zaps the invisible figure with his magical freeze-ray, sensing the arcane connection with the target. Immediately Rowan appears on the scene and swipes at the same spot with his elven sword, making contact. There is another curse and another scuffle of movement. Then the invisible leprechaun appears just a short distance away ... but superimposed within the image of the smiling, chuckling leprechaun (which, it is now clear to see, is an illusion). The real leprechaun is identifiable not only because it appears battered (compared to its twin), but also by the fact that it is holding a banjo in one hand ... identical to Mulligan's banjo in fact! With its free hand, the creature grabs a clay pot from its belt and launches it directly at Rowan, striking him. Immediately, Rowan feels sticky honey on his skin, which threatens to gum him in place!

The magically-oversided Barria stomps over to the hidden leprechaun and whomps it with her hammer. It too curses, then deftly slips away from her and flees a short distance, before launching a pot of honey at the her too! The pot strikes the dwarf, bathing her in sticky honey...

========================
Barria and Rowan: Please make DC 13 Dexterity saving throws, or become restrained.

There are now nine leprechauns visible: four identical pairs, and one extra. The five with unhighlighted nametags are all smiling and chuckling; the four with black-highlighted nametags are not.

* The leprechaun titled 'Lorcan' is covered in frost, standing in Rowan's emotion-vines, half-obscured by a smiling/chuckling illusion of himself, and has Mulligan's banjo on its back. Seeing this, Mulligan can now sense that his banjo is missing.

* The leprechaun titled 'Seamus' is holding Barria's frying pan, and there is an identical Seamus right behind him, smiling and chuckling. Barria now realises that her frying pan is missing.

* Immediately adjacent is the slightly injured 'Padraig', who is identical to the uninjured Padraig, smiling and chuckling off to the right.

* The leprechaun titled 'Fionn' is smiling and chuckling, but otherwise motionless.

* The leprechaun titled 'Tadgh' on the left is a little battered, and his uninjured twin on the right is smiling and chuckling.

(NOTE: Some items have been removed from the character's inventories, and placed in the "party inventory" tab.)

Party conditions:
Barria is Enlarged
Greginald is concentrating on the Enlarge spell.
Rowan is Raging (with option 7 active).

Battle Map:

Rowan, having had a lot of experience with people throwing things at him, quite often after he has played his lute, sees the pot of honey clearly as it sails towards him, and while he gets some of the sticky goo on his clothing he does manage to dodge the bulk of it and keeps from getting stuck to the ground.

Seeing that the leprechauns are now moving in to try and grab Polinella, Rowan ignores the one he was just fighting, and ignores that his lute, and apparently his bow too are missing and bounds around g'Reg and Mulligan and drives his sword at the frying pan holding small opponent (Seamus).

He swings, both hands on his sword again, and again recklessly intent on making contact than he is to protecting himself.

Longsword - Reckless Attack against Seamus - (8, 19 + 6) = 25 to hit for (6+4+2 from Rage) = 12 slashing

     Mulligan hasn't noticed his banjo missing and certainly not who has it, he's facing entirely the wrong way to see such.  Still, he does suddenly spot one holding Barria's frying pan!  

     That's not yours!

     He sends the thought out impulsively.  It would be laden with shock and annoyance, if his mental communications carried tone and inflection at all.  As they do not it just comes across as a statement in the leprechaun's head.  Still, the statement is followed by action.  Mulligan moves (NE) adjacent to the Seamus leprechaun (I don't believe he leaves anyone's melee) and attempts to "bump" into them "accidentally" and use the collision to subtly and sneakily replace the frying pan with a candle from Mulligan's own inventory.

(Kind of imagine a it like a sleight of hand magic trick / pickpocket maneuver...  I fully realize this may be pushing Sleight of Hand a bit far?  So if DM prefer some other disarm tactic I understand...)

Sleight of Hand:  12 only anyway...  (Damn I am rolling poorly of late.)

     Why "fecked"?  Perhaps we can work something else out to help you!

     Mulligan doesn't expect them to listen but it is worth a shot.  After all, it's not like they are really "attacking" the party in much of a physical damage kind of way...

Not truly understanding the limerick, Barria ignores it and as the honey washes over her, she runs a finger over her cheek where a lot of it is and tastes it.  It was some of the best honey she'd ever had, and they were throwing it away?!  What was wrong with these creatures??

Then she realizes she was stuck in place due to the delicious honey.  She stares at the leprechaun closest to her, Lorcan, and notices Mulligan's banjo.  "Mully!  This imp has your banjo!!  But don't worry, I'll give him song of his own."

Seeing that she couldn't hit him with her hammer, she rings the bells, hoping to bring the leprechaun to his knees.  WIS save 13 or 5 necrotic damage.

Seeing everyone occupied Reg spots tadgh and fionn to the West not being attacked by anybody. He moves to within 10ft of them and charts a short spell, a blast of thunderous energy emits from him and threatens to knock the two backwards. (Thunderwave Con save 14, 13 damage and pushed 10 ft away on a fail, half dam no push on success) 

If able Reg then moves back 5ft to be sandwiches amongst his allies once more.

Lightning and distant thunder have been part of the scenery since the passage through the portal, but it suddenly pays everyone a very close visit: Greg's magical thunder claps everyone suddenly on the ears: Tadgh's hat blows off, but he manages to stay in place, while Fionn doesn't even have so much as his hat-flower ruffled. It is clear now to Greg that the Fionn he sees before him is not corporeal, but must be an illusion. The illusory leprechaun continues smiling, then walks over to stand beside Greg and blows a raspberry at him. Greg's thunderclap is still echoing off the mountainside when a loud bell sound causes yet another smacks on the ear. The magic seems to have no adverse effect on Lorcan though, other than making him shake his head and scowl

Glister flexes his sinewy muscles, and thrusts his arms at Padraig, trying to pull the leprechaun away from the queen bee. Padraig wriggles out of his grasp, shakes a finger at the elf acrobat and sneers:

Ach! You've grabbed at me! Daring and Bold!
My secret, perhaps, you've been told!
But try as you might
You'll not win this fight
And will never claim my pot of --- Ouch!

Padraig's taunt is cut off as Amidor stabs him again with his tiny rapier.

Meanwhile, Mulligan tries a deft grab at the frying pan, but Seamus is too alert and twists out of his way. He seems about to offer a smart-aleck remark of his own, but doesn't even get the first word out before Rowan runs over and thwoks him with his sword.

Seeing their efforts so far have been stymied, Seamus and Padraig try a new bee-napping tactic. Padraig lifts an empty honey pot from his belt, and holds the lid while navigating the jar's opening toward the bee. Seamus meanwhile uses his hat to shoo Polinella toward the pot's rim. Their hands work quickly and expertly, and within moments the bee is inside the honey pot and the lid is slammed shut. With a triumphal cheer, Padraig tumbles backwards out of the reach of Amidor and Glister, and scurries away up the path. Tadgh immediately runs off with him, shouting out to the others that it is time to depart, and Lorcan immediately runs off in the opposite direction. Seamus, the other Seamus, and the other Padraig don't move, but the two other versions of Tadgh and Lorcan move in closer to the group, pulling faces and making rude gestures...

====================

Conditions:
Barria: Enlarged
Greg: Conc: Enlarge
Rowan: Rage(7)
Mulligan: none

Three of the four 'real' leprechauns are fleeing, while Seamus is not yet (he's still putting his hat back on). Tadhg and Lorcan were unimpeded, but Padraig was slowed by Rowan's vines and only made it a short distance.
Five moving/talking but 'illusory' leprechauns remain, obvious now by the fact they are visibly unaffected by attacks or spells, including Rowan's vines.

Battle map:

Rowan, seeing Padraig run off with Polinella and Seamus in his way, he reaches out and wraps an arm around around the leprechaun, seeking to grapple the small opponent.

Action - Grapple - Athletics (w/ adv from Rage - 5, 16 + 8) = 24