The first of these really is, is there any enemy AI for the AI Empires? If not no biggy.
There's AI, although, it might be possible that you need to install Python 2.6 for it to work properly. If you find an enemy system and notice all of the starting fleet is still there, it means the AI doesn't run as it should. If it works properly, the AI should fly around a little and even create colonies. However I'm not sure, how the recent changes impact the AI scripts, which haven't been updated for a while, I think. It's possible the stealth/detection system is a problem for the AI. I still need to thoroughly test 0.3.14 myself.
The second is this. I know that there is no combat system in place for 3D battles at the moment, however, I am wondering if there is some sort of quick resolve in place. This of course would be entirely dependant on if the first question was a yes.
Yes, there is a quick resolve system. Depending on the balance of power, battles can take even multiple turns now.