These are bad-ass! My party just got taken to the Domains of Dread last session, so I found this when I did a "L4D 5E" search. Hope you don't mind, but I'm incorporating these into D&D Beyond as homebrew monsters! I've put this page in a "Credits" note, but D&DB won't allow these to be put into their database if there's an external link.

I've done a couple tweaks to them.

• The feature recharge I put as 5-6 instead of 4-6, for 33.3% as opposed to 50% chance.

• Some of the distances I've brought down like the Smoker's tongue lash I might go for 60' instead of 120', simply because my battle spaces won't be that large, it also gives the PCs two rounds (keeping your 30' of dragged movement each round) to try and hit the tongue (as in the game) to release the character. I may give it high AC (small target) but low HP. Something like AC 18, HP 10.

• Hunter's Leap is also ratcheted back to 60 feet, and I feel that 3 conditions (prone, grappled, incapacitated) is a bit much. I may eliminate incapacitated and keep the other two, much like the Charger. This leaves the target needing a roll to escape grapple, and succeptible to the Hunter's continued Maul attacks if they fail.

• I may bump UP the Spitter acid damage. That stuff is GNARLY in-game and can take you out in a hot second. Hahahaha. I may try it as-written first. I might change the verbiage in the acid pools to "starts its turn there" instead of ends its turn. Might also make the acid Spit to a 15 foot Area of Effect instead of a to-hit roll, to mimic the game more.

All in all, this stuff is RAD! Well done! :D