If I fall in battle before my AI party members too, they very quickly attempt to revive me. I've even had my "shadow" (as Reinhart) revive my AI party member. But I've never been able to figure out how to do it myself. When I stand near the corpse, I see a shield pop up, but clicking the Use button doesn't seem to do anything, nor does clicking on the shield. So is it possible for me to revive an AI party member, and if so, how?
Yes, you can. You just stand next to them until the shield pops up and then hold the use button. White light will swirl around, and after about a second, your companion will get up if you don't get hit while holding it down.