The first question is not something we can test. We would have to ask. But is it worth asking? It wouldn't really help us in any way.
Think about it. If someone driving a Revenant drives it off a cliff at full speed, gets out, and then the Revenant hits you, your death wasn't caused by a revenant. It's one of those odd ones like collision damage or guardians or ect. A vehicle does not have AI traits. It doesn't think. It just is. It is used, by ones with AI.
What I'm trying to say is that since Halo 1, Vehicles have been commandeered by Elites, or whatever drives them. There have been no vehicles with AI. That's just how they started out, and it's how they finished. Even grunts pilot Phantoms. Marines with Pelicans.
What Bungie realized in Reach, is that they were pushing the xbox 360 to its limits, so they needed to scrap some things so the xbox didn't have to render so much on one screen. A simple solution? Shrink and turn the elites driving the Banshees invisible.
Oddly enough, looking at an Anonymous Pilot while it's on the ground will seriously drop the framerate.