Not really. You can code the AI to do certain things within reason, like force it to build larger stacks and most of the time attack only when it has a chance, but its nearly impossible to get it to defend settlements correctly (it defends the region at best).

Regarding which regions they want to attack, that is coded in the pathfinding of a map afaik.

Outside of that, the rest is hardcoded. Basically you can only suggest the AI do something but it won't always do it, and reloading during a turn seems to reset a lot of counters for the AI.