Hmm. Well, the easier character to play include Faust, Sol, Sin, and Ky. Sol and Ky have a moveset that really ease you into the basics of the game, and the more advanced techniques. Sin is a character with long and wide ranged attacks with generally easy to execute combos (once connected) though you have a IMO minor inconvenience in managing a secondary gauge (specific to him) that depletes when you use special moves, the Calorie Meter. Faust is a pretty good character and can poke pretty well, good long ranged attacks and his projectiles are more useful/intuitive than they may seem.
Slayer I understand a little less, but he's a primarily ground based character who generally relies on converting hits into huge damage, since his mobility is a bit limited. Your moveset (Dandy Step especially) can give you some mobility though. Potemkin...well you played a grappler character in VF right? Grapplers I don't understand much either, but in a game with lots of gimmicks (I mean that playfully =P) and dashing around, I think for him you have to live and die by the reads. He of course has good defense modifiers and super armor in one of his specials, plus assorted stuff to give him a little edge like his earthquake attack.
