Lost Lab of Kwalish

DEX save: 16

(Dorian's at E18 so I'm not sure if that's in range or not. If not, I'll take the damage back)

Dorian will throw a gob of acid (Acid Splash) at the strider. DC 15 DEX save or it takes 7 acid damage. If the newt warrior is within 5 feet of the strider, Dorian will aim it so that he's hit too.

Close enough. and yes he will also roll to save

Strider Dex: 16

Warrior Dex: 21

Both of the monsters are splashed with acid, howling and screeching in pain the strider eyes his assailant. 1

 The newt warrior falls to the cave floor.

Leann's attack narrowly misses the warlock.

Shutorn and Sam are up.   

We've got a Strider west of the rock and a warlock southeast.

Would I be in range to the warlock were I won’t have disadvantage or would I have to move 

Quote from Wile_E_Coyote >>

Shutorn and Sam are up.   

We've got a Strider west of the rock and a warlock southeast.

You're less than 90ft away, but you are on the other side of some rocks and there is the cave ceiling to consider and the fact that your shooting into mist, so my gut says overall it feels like disadvantage regardless of the weapon's actual range (150ft for longbow).

With that said, the strider is basically right in front of you.

"I'll take the strider, you get the warlock!" shouts Shutorn, as he casts another five magic missile darts at the strider, doing 19 points of damage.

The strider dies in a hale of magic missiles

Sam shoots at the warlock: 17 for 10

(No DA, despite prior discussion)

The warlock is struck by Sam's arrow and winces in pain.  He shouts in Primordial: "Imix, let my blade taste flesh!"

The warlock pulls from his belt a scimitar, the blade of which is instantly engulfed in flame as he sets hand upon hilt. He lunges forward and slashes at Leann!

flame tongue scimitar 22 for 5 slashing + 6 fire damage

Shutorn harvests the life energy of the dying strider to heal himself.

How many are left aside from the warlock?

It's just him. Players are up .

Dorian will attack, with help from his owl. Chill Touch Attack: 26 Damage: 12

After he attacks, he'll move so that the warlock doesn't have line of sight on him.

Huarache will go for him with everything he has, swinging his glowy sword against the newt's flamey sword. Echo will also Help.

Attack: 26 Damage: 11

Attack: 19 Damage: 11

If either attack kills, no it doesn't. Huarache will deliberately be non-lethal with the warlock; he needs someone to question about Vernell's location.

Rules clarification:

Per SRD, 'knocking a creature out' requires a melee attack, meaning no ranged attacks and spell attacks that don't have a melee attack component, (like booming blade) can be 'non-lethal'.  This aligns with the called-shot exclusion: you could no more call a shot in the leg in 5E than you could declare a headshot.

So... If that would kill him, (pending Dorian's Dex save) given that you know it can't be 'non-lethal,' do you take the shot?

At the Chill Touch Dorian delivers, the warlock points his finger at the necromancer and casts hellish rebuke (as a reaction) engulfing Dorian in a flare of fire for an instant. DC 12 Dex save for half of 5 fire damage.

Actually, Dorian has to make that save or he's at 0hp, meaning the warlock's 'Imix's blessing' ability is triggered passively, gaining him 5 temporary hp, enough to soak some of Huarache's damage and keep him going.

Huarache is making a melee attack; he's using his Moon-Touched Longsword.

But this still hinges on pocketmouse's save.

I forgot your blunderbuss jammed. Well then I assume you're still going with knock out.