I think you have an overcomplicated theory about AI implementation. I did several tests that lets me spawn and remove them on any map easily based on whatever event I wish.
In my opinion, I'm not over-complicating it. You need a structured design to follow as guideline for all levels so that the implementation is consistent across all levels. Map-specific mechanics aside of course, but I assumed the request was for AI presence in all maps.
I'd personally only design AI for all levels if it only kicked in when player counts are below 3 or 4 per team. And that would still mean you need to design what their purpose is besides simply existing. Not to mention that sending AI to objectives via waypoints and scripts would need a consistent implementation approach - but this is beyond my knowledge as I've never implemented AI in such a way before. Unless of course the design demands that these AI units are on base defender-only duty, but without changing the way the AI can identify targets beyond their generated space, this would cause issues, as Pushwall already pointed out. Creative work-around can be done on this such as creating a separate AI firing range pathfind generated region that does not connect to their travel space, but that's messy trickery and untested, not to mention a lot of extra work for each level.
Another lovely problem that we then ignore: generating pathfind on APB levels makes LevelEdit crash due to memory issues, because of their size. The tools were designed for box canyon maps of CamosCanyon-size. Now it is my understanding that new level tools are on the to-do list, but that's still quite a way off.
And icing on the cake; I'd personally want script logic that allows me to change AI behavior or send customs based on the health percentage of the AI unit. Meaning a way to make an AI unit "panic" or act more defensively once his health drops below a certain point, or start using a different weapon. I'd also like to see AI health reset to full if they remain unharmed for 2 minutes or so (essentially a modified functionality of the existing health regeneration effect), while ensuring the percentage based triggers still function additional times after such a health reset(s). And then some.