It's not possible to have separate VCs for the player and the AI.
Harad won't have any such settlements, so that's not necessary. But if the need arises, we are much better equipped now compared to TNS to help the AI do what it needs to do. Obviously we can't work miracles, but we can give the AI a gentle push in the right direction...- If Harad is to have a territory west of Gondor, give that territory a special Men of Darkness cultural bonus, or a governor with sufficient attributes to ensure the settlement does not revolt. The Governor could have zero movement points to ensure he does not leave the city, allowing it to revolt.
AI agents seem much more potent in DoM. Starting as RK and with Adunabar having 3-4 assassins in my lands, I usually get a couple of 'building damaged' notifications every turn for the first few turns (I rarely need to test more than that at this stage), mainly targeting my markets and military development.A further example of poor AI performance, which might be considered in the next mod, is that the AI does not seem to know what to do with spies and assassins deep in enemy lines. The spies and such Adunabar has in Gondor at the beginning of the RK campaign seem to do no more than provide an irrelevant cult of shadow cultural bonus.