1) We will not be dividing species into different factions unless they had more than one faction eg men with gondor, arnor, haradrim, easterlings etc.
2) No. Read the FAQ
3)We have unit lists, but we are not telling the public.
4)There will be a variety of rebel units, as this is the FOURTH age, and as such there are many wars and rebels. The orcs will get there own faction.