Actually it is possible to play rebels. I played it for about 20 turns and it didn't crash.

There are some strange/interesting stuff though:

-In the beginning you are at war with every other faction.
-You can build diplomats, but they are completely useless, because they don´t have any diplomacy options in diplomacy screen. So you will allways be at war with everybody else.
-Allmost every turn you have new random armies appearing around the world.



-At start you don't have any family members. No faction leader or heir. Later as rebel armies appier around the map you will gain some family members from rebel armies with generals and family member adoptions are also possible.
-These new family members dont't show up in family tree and can't be made faction leader or heir.



-You are losing money very fast, so you can't build anything.