Engaged as they are in conversation, the firenewts and their steeds are taken completely by surprise.

Mica races out from his hiding place and takes cover behind one of the pillars.  [Mica has 3/4 cover here, and can still take an action.]

Danica unleashes her spell and the stone behind the riders erupts with vines and other plantlife.  The westernmost creature pulls its clawed feet free of the plants with ease, but vines wriggle up its sides and ensnare the firenewt rider, and he is restrained.  [Danica can still move if she likes.  She has 1/2 cover if she stays behind the minecart.]

Round 1

1. Mica (can still take an action)
2. Mounted Firenewts (surprised)
3. Meili, Hew, Nalomanterys
4. Firenewts (Surprised)
5. Ran, Danica (can still move)

With the attack on the going now and some enemies properly restrained, Meili simply darted across the oven-hot room towards the fire-newt smiths with her sword ready, hoping to stab and kick hard enough to down one of them.

[Attack on the closest one (should have enough speed)]

Shortsword Attack:       7 Damage: 7
Flurry of Blows Attack: 6 Damage: 5
                            Attack: 7 Damage: 7

Mica pulls out his longbow and leans against the pillar as he pulls back the bowstring and targets the closest firenewt working the forge.

Attack: 23 Damage: 8.

.

Ran takes off after Mica, the fleet ranger again moving faster than the fighter. He'll make it as far towards the riders as he can using his full movement, then getting ready for any potential charge or attack they send his way.

Action - Readied Longsword: Attack: 16 Damage: 12  

Danica charges into the stiflingly hot room with Ran, rushing past the pillar where Mica was hiding. She trusted that Nalomanterys would stay hidden and support Meili with fighting the firenewts working the forge. Shield at the ready, the elf was focused on the riders, and their captives more specifically. The last thing she wanted was for them to be victims of the battle. 

Seeing the need for speed, Nalomanterys grabs a pinch of soot off the floor and smears it on Ran's and Hew's faces. "Celero!" He chants, longstrider upcast to level 2. The debris on the Dwarven floor recognizes the two fighters, and will move out of their way, essentially speeding them up. The wizard then gets behind the wall one square to the right of Ran and waits for a new opening to help.

Mica's arrow flies wide, but Meili closes into melee distance and pummels one of the smelting firenewts.  It isn't finished, but its armor is dented, and its body is squished and bruised after her assault.

Ran and Hew both take advantage of the extra speed imparted by Nalomanterys, with Ran taking up a ready stance and Hew racing past.

Danica dashes toward the riders and their unconscious dwarven prisoners.

ROUND TWO:

1. Mica
2. Firenewt Riders and Mounts
3. Meili, Nalomanterys, Hew
4. Smelting Firenewts
5. Ran, Danica

Mica curses as his arrow sails wide.  He moves to the northwest, heading behind the second pillar to close some of the distance to the riders, then turns back and sends another arrow toward the firenewt in combat with Meili.

Attack: 16 Damage: 8 plus 5 colossus slayer damage.

.

Mica's arrow finds its mark this time, plunging into the wounded firenewt with a squelch and dropping it dead.

The first of the firenewt riders gives his mount a kick and the large bird/lizard horks up a small fireball, launching it near the SW corner of the smelting pit.  Danica, Hew and Ran must all make a DC 12 Dexterity saving throw, taking 10 fire damage on a failed save, or half as much damage on a successful one. 

The creature then strides forward on its long red chicken legs to the space adjacent to Danica and Hew, and the firenewt rider makes two attacks against Hew with its scimitar.

Scimitar Attack: 13 Slashing Damage: 7

Scimitar Attack: 12 Slashing Damage: 3

The other mount attempts to stride forward as well, but its rider is unable to extricate itself from Danica's vines.  It is yanked backward out of the saddle and falls to the floor, taking 1 bludgeoning damage.  Its mount continues forward undeterred.  Undirected, it still seems to identify the party as foreign creatures in need of extermination.   It moves alongside Danica and tries to bite her with its hooked beak, which glows like hot iron.

Bite Attack: 18 Piercing Damage: 11

1. Mica
2. Firenewt Riders and Mounts
3. Meili, Nalomanterys, Hew
4. Smelting Firenewts
5. Ran, Danica

Hew save:  23

Hew sidesteps both scimitar attacks and returns a pair of his own, targeting the large reptilian mount rather than the rider.

Scimitar Attack: 21 Damage: 13

Scimitar Attack: 21 Damage: 7

Ran Dex Save: 17  

Meili's attention was concentrated on the creature (fortunately only one now) in front of her. The smiths did not drop quickly but they did drop. She attacked again:

Shortsword Attack: 18 Damage: 6
Unarmed Strike Attack: 18 Damage: 4

DC 12 Dexterity saving throw for Danica: 7

The scent of burning hair caused Danica's nostrils to flare as the fire that they were attacked with singed both herself, Ran and Hew. She managed to step to the edge and raise up her wheel shield just in time to prevent getting a face full of fire, but while she was defending against that, the strange mount ran up to her. Twisting around, she couldn't bring up her shield in time and though she attempted to draw upon the stars' power, their light seemed to sputter before they could fully form. Screaming as the red hot beak bit down deep into her shoulder, steam rose from the wound before the elf's green eyes rolled back into her head. Danica slumps limply to the side, unconscious. 

Nalomanterys rolls up his right sleeve to better perform a few short but intricate arm movements. The wizard stares intently at a hunk of coal sitting in the bags next to Meili, and with a final flick of his wrist, the black rock leaps from its perch and soars unerringly at the head of the Newt that Meili is entangled in combat with. ((catapult aimed so that if newt 1 dodges it, newt 2 will also have to make the save... if catapult works that way in your world))

Dex DC save 14

damage 20 magic bludgeoning (rolled in game log)

Meili lands a blow against the remaining Firenewt smelter.  It dodges her other attack... then its eyes widen in horror as it just ducks out of the way of a supernaturally embiggened lump of coal.  The coal smashes into one of the smelters behind it with a crunch.

Looking around in confusion, the remaining Firenewt barks something in their harsh tongue toward the riders and then flees, running up the small stairs behind it and up around the back side of the smelters, toward another doorway.  [Firenewt dashes away from Meili, traveling 60'.]

Ignan/Primordial:

 Meili can take an AOO if she has a reaction left.

Ran is up, and Danica is down.