Fianna drops the guy.  "Ok, then...  Now what?:

That's when the arrows strike. 

Two long-haired young men, twins by the look of them, each armed with longbows and clad in leather, have somehow materialized in the dark, southwest corner of the room. How they entered the room is a bit of a mystery. Even Lucky, who was keeping an eye on the stairway leading up to the trapdoor, didn't see them.

Bowman #1:
Bow attack #1 vs Lucky : 10.  Piercing Damage: 7
Bow attack #2 vs. Katernin: 17.  Piercing Damage: 5

Bowman #2:
Bow attack #3 vs Reed: 9.  Piercing Damage: 7
Bow attack #4 vs old man: 17.  Piercing Damage: 4

 Lucky is struck by the arrow, and Katernin manages to turn hers with her chain mail, but the other two miss their marks.

Initiative:
Bowmen:  18
Fianna:   14
Katernin:  3
Kelnan:  23
Lucky:  5
Molo:  10
Reed:  22

 Everyone but Reed may act. Lucky is about fifteen feet away from the attackers, Molo 75 feet away, and everyone else is 55 feet away.
 

Kelnan

"I was fine with the door plan, but I'm willing to compromise if you help us out, old man!"

He raises his arm and fires a Ray of Frost at the nearest bowman, then tries to duck behind the table, not eager to feel the sting of another arrow.

Attack: 21 Damage: 3

Molo yells at Lucky “I still think you’re lucky!” for a d6 inspiration!

He says this as he runs towards the bowmen and when he stops he shouts “Your arrows hit the mark about as often as your life has!” casting vicious mockery DC 13 Wis save 3 

(OOC: waiting to see if anyone is going into melee before I either join them or run away!  Not going in solo as I can't use Sneak Attack solo and am not designed as a front liner!!)

     Fianna mutters some arcana words and points at the most southern (bottom) newcomer and casts an Eldritch Blast Attack: 8 Damage: 7 and then runs towards the attackers, trying to get too close for the bows to be effective.

Racing forward, Fianna fires a beam of eerie crackling energy across the room, missing the twins narrowly and filling the room with a brief, unworldly purple glow. Fianna dives behind one of the beds (still within bow range at 25 feet away - she'll need to get within five feet for the bowmen to be at disadvantage - but the bed gives her +2 AC bonus for half-cover.)

Kelnan takes a few steps forward and fires a similar arcane beam across the room, but an icy bluish-white in color. Frost forms on the thigh of the northernmost bowman; he winces in pain and shifts his weight. The nimble wizard then dives behind the table (also granting +2 AC bonus for half-cover.)

Molo races toward the middle of the room, lobbing a psychically-charged insult at the frost-covered bowman. Wisdom save: 16
 The long-haired goon chuckles at the kobold's taunt.

Movement: 30 feet towards the men

Action: Cast Sacred Flame Dex save 13 or take 1 radiant damage at one of the men.

Katernin takes her mace and moves towards the men as far as she can, snapping her fingers to cause radiant flames at one of the men as she does so.

Katernin races forward, uttering her spell. The southernmost goon dodges the glowing radiance that descends from above. Dex save: 15

 He twists and sidesteps Katernin's holy flames.

Lucky is up next!

(Is anyone adjacent to the bad guys?  I'm not 100% sure?)

(Nobody has made it to the bowmen yet.)

Kelnan and FIanna have half cover (+2 AC). Lucky is up next, then the bowmen.
The old man scowls, spits, and watches, tied-up in the back of the room, behind his fallen comrades.

Lucky will duck down behind cover.   

(Assuming there is some structure to the staircase, can I gain full cover from moving behind it?  If possible he will hide there for now.)

Stealth: 23

Lucky finds a hiding spot behind the staircase. It's not full cover - it's a crudely-made staircase that was clearly added in recent years, and the base is not fully enclosed. (3/4 cover: +5 AC)

The twin bowmen smirk, and let fly another volley of arrows.

Bowman #1: 
Attack#1 on Kelnan: 19. Piercing Damage: 8
Attack#2 on Reed: 14. Piercing Damage: 9

Bowman #2:
Attack#3 on Katernin: 8. Piercing Damage: 4
Attack#4 on Katernin: 14. Piercing Damage: 3

  Kelnan takes an arrow to the stomach under the table; Katernin catches a very unlucky arrow to the neck in a gap in her chainmail. Both go down.

Reed lets an arrow fly at the northernmost attacker:
Short bow attack: 21.  Piercing Damage: 9

His arrow narrowly misses his mark.

Everyone except Reed may act. (Nominal order: Fianna, Lucky, Kelnan, Katernin, Molo.) 
Kelnan and Katernin may make Death Saves.

((Welp I'm down good luck))

Fianna repeats her previous action, casting Eldritch Blast at the southern intruder, then rushing to close the distance.  She's worried about Katernin and Kelnan, but has no way to heal them and even treating their wounds is ill advised while they are all still under attack.

Eldritch Blast Attack: 21 Damage: 6

((I'm convinced there's some secret purchase you have to make from D&DBeyond to get halfway decent dice rolls...))

Fianna sprints forward, firing her purple beam and searing the man's cheek with its force. His smirk fades and she closes the distance between them.
Lucky, Kelnan, Katernin, and Molo may go next.

Death Save: 16

Kelnan

Not again...

Death save: 2

Molo rushes towards Katernin and lays a hand on the arrow wounds. “Live by the sword, die by the sword... but these are arrows.” Casting cure wounds healing 6 Hp (forgot, add 3 more to that. 6 hp

(I really hope you’ve got some juice left to help with the other dead guy)