Initiative: 21

Rori is prepared to rush in first with the clear idea she may not survive but it should start the fight in a favorable way.

Initiative: 14

She'll get within 15 feet of the group of goblins, and then slap her hands on the floor to cast thunderwave . The sound is deafening in the small chamber as thunder booms and reverberates off the walls.

Saving throw to beat is Con 13, if they fail the full damage is: 7 thunder damage and pushed 10 feet away from me
If they succeed, half damage

Jubilee is going after the super goblin 

Initiative: 9

(Before any of the evil creatures inside the room can react, Rori runs in and casts Thunderwave at the 3 Goblins standing to the side! The Goblins brace themselves as best they can.)

Goblin 1 save: 20

Goblin 2 save: 15

Goblin 3 save: 16

 ok, mine says Unable to parse rolls, I'm going to roll 1 for all 3 in this new post.

7

 (Rori's Thunderwave catches the Goblins completely off-guard, and the 3 of them are instantly killed by the effects of the powerful spell.)

"What the!? How dare you!? You'll pay for that! Shaman, don't stop!"

For DM only:

(The Bugbear grabs a Javelin from up against the wall, aims and hurls it at Rori!)

Attack: 16 Damage: 4

 (The Javelin slices Rori's bicep with a nasty gash, but it luckily didn't hit anything major. It's a lucky, close call for Rori.)

Gaberin, you're up.

Gaberin will cast Entangle on the bugbear

If it is the modifier, that's only plus 3, so this roll minus 2. If it is spell attack, this is correct.

16

DMs note: It actually just works, when it's the Bugbear's turn they'll have to do a Strength Save to see if they can get loose.

(Vines sprout up from around the Bugbear's feet, entangling it and slowing it down significantly. The leader yells in rage as it struggles against the vines.)

Rori, you're up.

Rori will run her hand through the cut in her arm, swiping the blood on her fingers. She’ll flick the drops of blood towards the goblin in robes and bugbear and say, “A little dark in here, don’t you think?” As she says the words, a violet light glows around each object in a 20 foot radius surrounding the goblin/ bugbear (my allies shouldn’t be there yet). 
Rori will turn to Gaberin, barely through the door, and say, “Hold that Bug Bear like your life depends on it, cause I think it might!” Then she’ll turn and run away from the enemies.

Action: Casting Faerie Fire
Dex save 13

Bonus Action: Bardic Inspiration to Gabe (1d6 that can be used on a saving throw)

Movement: Rori will back up to the nearest wall as far away from the bugbear and goblin as she can get (at most 60 feet from them)

DMs note: Since the Bugbear is Entangled, it's going to have Disadvantage on this roll.

 Bugbear Dex Save: 7

 DMs note: From this point forward, any attacks against the Bugbear have Advantage.

(The spell works and the Bugbear is outlined by a green light. As a strange coincidence, the wall behind where he was standing also lights up a light blue in the shape of a door. Most curious.)

"Shaman, help me!"

(The Shaman turns from the spell he was working on, breaking the hours of work he had been doing. It starts doing something with it's hands, and a Fire Bolt appears, being thrown at Rori!)

Attack: 9 Damage: 4

 (Rori jumps out of the way and the Fire Bolt goes wide.)

Jubilee, you're up.

Quote from stiffkick80 >>

 DMs note: From this point forward, any attacks against the Bugbear have Advantage.

 

(The spell works and the Bugbear is outlined by a green light. As a strange coincidence, the wall behind where he was standing also lights up a light blue in the shape of a door. Most curious.)

 

"Shaman, help me!"

 

(The Shaman turns from the spell he was working on, breaking the hours of work he had been doing. It starts doing something with it's hands, and a Fire Bolt appears, being thrown at Rori!)

 

Attack: 10 Damage: 2

 

 

 (Just curious: did was the shaman within 20 feet of the bugbear? Faerie Fire would’ve hit him too)

You know, you're right. Ok, hold on.

Shaman Dex Save: 8

(The Shaman also appears to be surrounded by a green light.)

Jubilee enters rage and pulls her greataxe from her bag on the ground. Running into the room, she swings at the super goblin. 

Attack: 16 Damage: 15

Oops, Jubilee, you should have done this as with advantage. Go ahead and roll 1 more normal attack roll, no advantage, and we'll use the higher one of the two.

15