Hmm, personally I'm not too fond of including Branded.
I suppose I'd be okay with Branded existing in the world as NPC (as pointless as that seems) but every FERP I've participated in has been overrun with Branded [s]and Myrms[/s] and it gets really boring. Even with limited spots, I don't agree with the first-come approach. I suppose I'd be okay with a Beorc character that's privately negotiated to be a Branded and not known to fellow players, but otherwise... ehhh.
 
If we want to do the whole persecution thing, I'd much rather see it incorporated as Laguz being seen as inferior by humans, and laguz tribes holding certain attitudes towards one another. 

Branded are setup in a way that's a bit too Mary Sueish for my liking, just my preference. It's not a dealbreaker for me, but personally I'd prefer them omitted. I'm aware that this is going to be based on FE, but I'd prefer the RP not copy/paste the FE lore/setting of the GC/Wii installation.

As for Laguz types?
I sort of think it'd be better to remove all original Laguz tribes, and have players contribute their own set of Laguz. For example Dragon Laguz might be completel omitted if no one wants to play one. Whereas a rabbit Laguz could be incorporated instead if there's a keen player. Laguz tribes can be fun, as long as it doesn't become obsolete clutter.