I just booked a F award to Europe using YYZ on the out and YVR on the return. Thought I'd give BA F a whirl as people on this board speak highly of it.

Thing is, I've never flown in and out of Canada.

On the outbound, do I have to do any immigration into Canada or am I just a transit passenger. Is there a terminal change. I can't seem to find much gate info on the BA website.

On the return I overnight in Vancouver so I know I will have to do Canadian immigration and customs. Which is better to use, an American or British passport?

Flying YVR-DFW the following day, how does US immigration and custom work on that? Is it the full thing just as if I was flying in from London.

Sorry for the dumb questions. I've been to just about every country in the northern hemisphere but always manage to avoid Canada. Until now.