I mean, I enjoy making up OCs and 'move-sets' and the like as much as the next guy, but 'removing' all of the characters that make up most of the source material's story [perhaps all of it given that the games are all about the characters and story tends to be secondary] just seems like an unnecessary complication. xD

If I might make a suggestion, It'd just be easier to use the 'canon characters' as a sort of... 'guide' to their character in RP, but not be worried by the idea of playing them 'right'... if that makes sense. It simplifies the roles that would be vacant without them, without the complication of having to fill those roles back up 'incase' you don't get enough people to do so.