@KoL This is just a suggestion, but in helping to make balanced teams, would it be useful to break the characters down into general roles? Such as Attack, Defense, Agility, Support and Control?
For example Kurenai seems more like a hit-and-run Agility fighter, made to harass enemies and unbalance them, allowing a Control character like Charles Anderson to make them sitting ducks for a heavy attackers, like Tatsu appears to be, to wipe them out more easily.
As I said, just a suggestion :)