[Capsicum]

Also, if someone born in Germany at a young age, and moved to the US (even getting citizenship there), and then moved to Canada, would it really show up as an "American" moving to Canada, or merely a German immigrant moving to Canada?

I think immigration generally treats birthplace as being where someone immigrates from, right, so even though a person might have passed through many places along the way, it's generally recorded as person from (birthplace) immigrating to (final destination) rather than person from (last previous destination) to (final destination).