Dusty is a cat, isn't he? Have we seen/heard of non-human minions? After reading some info on the game I agree he would be the best pick, but I'm not sure he would transition to "chibi" well.
Kuma heihachis bear is a minion, I don't see why dusty can't look like a chibi.
I see dusty as just kind of hanging around her during the actual match, just like in her game. Gade or Raven would be the best bet I think.
Raven might actually be a good idea for the minion.