Human factions are likely going to be of very little to no consequence in this RP. Sure, humanoid races will be everywhere, but humans themselves are pretty much like a speck of dust in the grand scheme of things. On top of that, humans aren't exactly an original species, so be prepared to compensate for that.

Along with that, there will be others already wishing to play as humans, so there will be painfully obvious constraints even there in the realm of what you can do with them.