Sky and Fellow, you two are currently it. So I will open this up by saying that we have lots of ways that we can approach this. I can take care of removing inactive members, so don't worry about that.
So some of the choices, just to get the ideas flowing, include a wave type battle where our characters fight progressively tougher enemies, one battle in which we fight extremely skilled/powerful enemies, a tag battle, an elimination battle... you get the idea.
So what combination do you guys think would be the most fun? Personally I like the single battle against highly skilled and powerful enemies, but we can also mix an match ideas here.
So shoot.