the easiest way i can think of (doing this for my gamemode ppl vs dinos) ofc we need the next update so we can play with the default character but u just grab the “default character pawn” and a “dino” (in my case all the dinos) pretty much clear all the ai ect and then add the character graph and essentials i cant see u needing an inv but u then need to change how it spawn. eg. “if its a person spawn choose a person char” then “if its a dino spawn bring up the dino choose menu, then base the character off what one is chosen” as a basic eg. if u need more help im here 
it really depends how deep into being the dino u wish to be