@Riffus Maximus Actually, I was thinking of limiting it to one for now. A panther would be great. Also, since Henkei-type abilities need to be activated, they tend to be more than just alteration of physical traits as opposed to Igyo-types. I know it seems kind of boring to have it limited to one, but I assure you, progress in the RP is going to be relatively fast. Or at least that's what I'm hoping for.
If you start with a single animal as a base, it'll open up your options when power-up time comes. You could go for other transformations or further improve her panther form. Maybe assimilate some sort of element into it or associate it with a concept or theme. Or slowly stray from a mere panther into something more chimera-like?
EDIT: Go for it, just don't pack too much into it. You'll all get more skills and abilities throughout the RP anyway.