I really don't like that idea. Monkeys could not ride motorcycles, mainly because their legs are too short to reach the pedals-- and that would mean the bikes would have to be redesigned.
So, since the bikes are great the way they are, we can't have monkeys in Full Throttle. Besides, if you want monkeys, that's what Monkey's Island are for.
I think FT2 should set up the story for FT3.
But I don't know what that is yet.