Using the stealth to his advantage and getting a bit of surprise on the mob, Shishakli focuses on one of the possessed and fires of a couple quick arrows at it.

Nicholas takes aim at another Myconid and fires his pistol again while shouting, "Please stop! We don't want to have to hurt any more of you!"

He then moves to make sure he keeps a distance from the advancing Myconid.

Action: Fire Pistol at Myconid. (2/4 bullets before reload) Attack: 15 Damage: 5

Seeing the swarm rapidly overtake her dwarf companion, Syvis drops her crossbow at her feet, draws a dagger from each hip, and flings them at the nearest aggressor (splitting one off to a different foe if the first drops).

Action - Attack: 17 Damage: 7
Bonus action - Attack: 17 Damage: 2
Sneak Attack: 5

Thodek easily pushes the hungry spores back and resists their effects.

Nicholas then takes a shot, and it blasts through the shoulder of a mindless myconid that gives only a moan of pain in response (-5hp).

Syvis then draws two daggers, flicking them towards another myconid. Both sink deeply into the creature’s hide (-17hp).

The friendly myconid move as far back against the cavern wall as possible while Basidia (noticeably larger than the rest) takes a protective stance in front of the rest. They will all take the dodge action. 

Shishalki also fires two shots at a third uninjured myconid. Each arrow strikes true and you see the creature fall as green ochre like blood spurts from its wounds (Dead). 

Finally, Thodek brings his hammer down on the myconid injured by Syvis and is able to bring it down with a sickening crack (Dead). 

And, as both these two myconid also fall, spores again erupt from their corpses and swarm towards Thodek. Please make two more Con. Saves. 

 The now 5 still standing myconid each swarm Thodek and attack the powerful dwarf.

Attack: 6 Damage: 5

Attack: 16 Damage: 6

Attack: 21 Damage: 4

Attack: 14 Damage: 4

Attack: 4 Damage: 4

Only one from the onslaught makes contact, the rest either parried or blocked by Thodek’s steadfast armor and shield. However, as the strike makes contact, a pulse of poison shoots through your body dealing 3 poison damage (Total: -18hp). 

 Nicholas is up! Everyone else may also queue actions to speed things up if they would like. There are 5 myconid left, one slightly injured. What would you like to do?

Thodek con save 1: 18   2: 11  Concentration check: 12

If he's still up, Thodek will chant quickly to restore health to himself before swinging again with his hammer.

Healing Word: 9
Attack: 16 Damage: 7 + 3

From the darkness you hear the voice of your gnome companion suddenly say, "It seems they cannot be reasoned with... they are too far gone." followed immediately by an arrow streaking out towards another of the 'infected'.

With Thodek constantly being assailed, Nicholas will do his very best to aid his friend taking two shots in quick succession and emptying the pistol's chamber.

Action: Pistol attack (1/4 bullets before reload) Attack: 18 Damage: 7
Action Surge: Pistol attack (0/4 bullets before reload) Attack: 8 Damage: 7

Using [feat]Lucky[/feat] to reroll the Action Surge attack 15

Syvis sighs, scoops up her crossbow and rolls to find some sort of cover before firing.

Stealth: 16
Crossbow - Attack: 13 (or 17 if advantage from hiding) Damage: 4 Sneak Attack (if applicable): 9

Thodek: Concentration maintained! Also, my bad on the con. saves. After resisting one, you can’t be affected again for a time… You notice that as the spores dive in to envelop you, they appear to be pushed back by some invisible force and dissipate from the air. 

Nicholas takes two more shots. The first makes sickening contact, and the second also does as well, though appearing to miss for a split second. They both strike an uninjured myconid (-16hp).

Syvis rolls away, into the shadows before once again drawing her crossbow. In the thick of the battle, none of the mindless myconid seem to notice. You let a bolt loose toward the same creature just injured by Nicholas, causing it to sink to the ground, dead (Dead).

The friendly myconid continue to dodge, although oddly enough do not seem to be of any concern to the mob of enemy myconid. 

Shishalki fires an arrow at another uninjured myconid, the force of the shot causing the creature to stumble backwards, but stays standing (-14hp).

Thodek then follows up on that shot, by bashing in the head of the momentarily open creature, finishing it off (Dead). He also murmurs several words under his breath and feels invigorated (+9hp). 

 Two more down; that leaves three. Each makes an attack at a now looking more rough Thodek.

Attack: 4 Damage: 2

Attack: 10 Damage: 4

Attack: 8 Damage: 5

However, all three again miss.

That means Nicholas is now up! Everyone else may also queue their actions if they would like. Three myconid left, one slightly injured; What would you like to do?

Syvis stays still in the shadows, knowing her position was given away by her last attack but chancing it to take careful aim for her next shot. At the last moment, she remembers something in her pack that she totally knew was there before checking her inventory a minute ago and definitely very specifically remembers where it came from. Drawing out another bundle of crossbow bolts, she loads one dipped in drow poison and fires it at Shishalki's target.

Crossbow - Attack: 9 Damage: 11

Knowing there is little else he can do, Shishakli continues to fire off arrows, sorry to see these poor shroom folk taken out, as they had always been so friendly to him in the past.

Attack: 12 Damage: 11
bonus action move hunters mark if needed.

Thodek mutters another word of healing and swings his hammer down on another of the myconid.

Healing Word: 5

Attack: 8 Damage: 5

With the chambers of his pistol emptied, Nicholas takes cover while he reloads the weapon.

Move: Take cover
Action: Reload Pistol

Nicholas moves further away from the myconid, and takes some time to reload his pistol. (There isn’t really any cover up here on the terrace, but the myconid don’t really seem interested in attacking any of the ranged attackers. They really just seem to be in a frenzy of sorts attacking Thodek who is closest.)

Syvis draws a bolt from her case of Drow poison, taking aim, but the attack misses, firing just wide of the creatures (Miss).

Friendly Myconid continue to dodge

Shishalki shoots another arrow, targeting the injured myconid. It makes contact, but does not fully take out the creature (-11hp (Total: -16 hp)).

Thodek then attempts to finish the creature off, but it is able to dodge his hammer swing at the last second (Miss). He also looses another healing word to nourish himself (+5hp).

Enemy Myconid are up! Three more ravenous attacks directed towards Thodek— the myconid in what appears to be a bewildered frenzy of rage.

Attack: 17 Damage: 6

Attack: 3 Damage: 8

Attack: 8 Damage: 3

Again, all three miss, or are blocked by the steadfast cleric.  

Party is up again! Please all make/queue your moves. There are still three myconid left, one slight more injured. What would you like to do?

Syvis closes her eyes for a split second, taking a deep, centering breath, and takes aim once again. She fires her crossbow and follows it with with her final flung dagger.

Crossbow - Attack: 7 Damage: 5
Dagger - Attack: 18 Damage: 4
Sneak attack - Damage: 5

EDIT: Still aiming at the same enemy.

Weapon reloaded, Nicholas returns to the fray and fires at yet another myconid, "Hang in there Thodek!"

Action: Pistol attack (3/4 bullets before reload) Attack: 21 Damage: 5

Thodek summons up the last of his magic to heal himself once more as he swings his warhammer, grateful he'd imbued his armor with his god's blessing.

Healing Word: 6
Attack: 18 Damage: 7

Looking around to ensure that there are no other dangers looming, and continues to shoot at the infected, knowing they need to be put down.

For both simplicities and speeds sake, we will say that you all are eventually able to dispatch the last of these rogue myconid. 

No one takes any more damage, and as the heat of battle ends, the clouds of spores that have been erupting from the heads of myconid who are taken out slowly thin out and dissipate (after around a minute).

Thodek though also may still gain +6hp if he chooses to do so.

Slowly but surely, and led by Basidia, the rest of the friendly myconid also walk over to your group. Clouds of rapport spores begin to envelop you as the creature begin to reach out again to communicate with you.

Accompanied by a soft cacophony of unintelligible myconid rambling, Basidia begins to speak. “Thank you very much, softer friends.” The sovereign says. “Obviously… we had found ourselves in a tough spot.”

Basidia is surrounding by around 10 other myconid which you can assume to be members of the circle of growers that cultivate new myconid sprouts. On top of this, she carries a large box that appears to be made of zurkhwood and carries an earthen stench. 

“Now tell me, what did you discover in the Garden of Welcome?” Basidia asks. “Might it have anything to do with the... horrors we just witnessed?”

 What would you like to do?

"It is far worse, I am afraid," Syvis begins. "There was a grotesque creature planting humanoids in the soil and sustaining them in some sort of unholy undeath. We have destroyed the creature and razed the cursed field but I fear that is not the end of the horrors. There was talk of a wedding and mention of some sort of beings called 'the Great Seeder' and 'the Great Body.' Do you know of them or this wedding? It sounded imminent."