1) That's what warranties are for. All new cars have expensive parts that will eventually break. From what I've read, the pump does seem to fail in a bad way, but I don't think of it as a real worry.
2) Just pay attention to what you're doing.
Pennsylvania isn't one of those annoying states where they make someone else fill it up, is it?
3) That is what I've heard as well, but VWs (& I would assume the A3 as well) have a heat strip in the heater that will turn on to at least warm the air a little. I got mine in March, so I haven't had much of a chance to test it.
The Prius may appear larger, but I'm not sure it really is from a usable interior space perspective. And I think it might be more like 1000x better.