Dex-Based Gun-Using Grunts

Alright, so a buddy of mine wants to GM a campaign thats sorta like Fallout(Post-Apocalyptic) and Last of Us (Human-plant hybrid things), and we are trying to make stats for the enemies and so far we have an idea for one group of enemies and they are Dex-based Gun-Using Grunts. So if anyone has advice on how we should make them, please share as that would help immensely.

EDIT:These are NOT the plant hybrids

Fighter (Trench Fighter) 3

Trench Fighter 3 would make for some fearsome gun-toting grunts indeed. But regular level 1-3 Warriors with the proficiency and focus feat should do just fine. Of course, point blank/precise/far shot is always welcome. I usually don't bother with PC classes for grunts. They're called "grunts" for a reason, after all. Just use the base stats for ranged NPCs and follow the guidelines is what I'd say.

give them muskets or shotguns and who cares about what feats etc, they are shooting touch ac.

If it's post apocalyptic guns could be everywhere and therefore firearms would be simple weapons, hello pistol wielding rogues.