I think the best representative of Neo Geo beat em up titles would be Maxima from Robo Army. Not only with moves from his source game, but also with stuff inspired by his KoF appearances. He could also kinda represent BoR itself in the game. For a TG16 character, there was this all-female beat em up called Ane-San, that could get its protagonist (Ai) and maybe more (like the pop singer boss (Ruri ) or the swordswoman boss(Sohshi) or one of the other protags ) included. Or at least a stage for it.
Edit: I also kinda want a Mutant Rampage: Body Slam character.