Ah the scripting aspects look great!

Does the "Rebel" faction remains a faction like the others in it's habilities or is it something more vast without unit or model limitations, like the ability to have several different culture types for Generals (read family members) and Lesser Generals (read captains).
I haven’t gone into this in detail, but the mechanics behind the slave faction appear pretty similar to Rome.
Don't know if this helps, but rebels are listed as a faction which everyone is at war with in the diplomacy options