Can I have one faction have both Occupation mode and Asymmetric mode? Pretty much, the idea is that one AI faction is the occupying force on the island and when they are invaded, the occupying forces react in an Occupying force manner. But, as the Invading forces gain ground, the civies and such on the island start to become more Asymmetric to help support the occupying forces against the invading forces. I guess, have one AI faction be both Occupation and Asymmetric. I want to make a campaign where there are 2 AI factions duking it out and the 3 faction controlled by players (PMC) rolls in to get its piece of the pie. But have to be careful of the civilians on the island and how we treat them because they might start IED our forces.

You would need three opcoms. One for the occupation force, one for the Asymmetric, then one for the invader. Remember the overall unit control is by faction rather then side. So you could have Opfor as the occupation, then Opfor_FIA for the Asymmetric side.

The third would be your invading force. You will have to adjust a lot of the army size and competition to get the flavor your wishing for.