About point 3: I'm away from my gaming computer until the end of the week, so this is not firsthand knowledge, but from what I understand the UA drifts towards the planet at about 7m/s, so it would probably take anywhere from weeks to months of following a UA, depending of distance to the planet, for it to reach the planet surface. So I doubt it's an experiment that we can do in-game, but I'm happy to be corrected.
Do they always descend at 7m/s? I was wondering if their planetfall velocity changes with the planets gravity. If it doesn't I think that raises a couple of questions.