Pitfalls for characer/animations on the iPhone

Hi, I'm in the process of hiring someone to model and animate a character for me that I plan to use in an iPhone game, apart from the obvious polycount issues is there anything else I should be aware of?

I remember reading that only certain types of bones/animations are supported?

If theres anything else you know I'd really appreciate it, theres nothing worse than getting to the end of a project and finding out you've made a big mistake :)

Thanks guys,