Heres What I've seen so far,
For the diplomacy section on the map screen to display anymore than the status of relations, you need to be the commander and there needs to be a human commander on the other team you want cease fire/alliance with.
You can build AI static defences around outposts
You have to be near a factory to buy units (no remote buying as far as I can see). Also you cannot buy while in a vehicle you need to be stood outside.
The insurgents cannot get planes/helecopters but do get cheap vehicles/troops. And the best ski masks!
I've only had a few games and this is a brilliant scenario, the sooner the servers fill up the better, the most I've seen on a game so far is 10 :confused: but it early days yet.