1. export as .obj
2. keep the poly count low, but don't be afraid to flesh out details
3. texture first animate second.
but I still need to know how you want the models animated to work with minecraft.
If you code in the animations when adding them, and if the pieces need to be seperate objects, just cut apart and rigged, or just not sharing any vertices.
I'm planning on modeling Growlithe and Arcanine to start though.