If you graduate from a US PharmD program it shouldn't be any more difficult since you technically aren't an "international graduate." The only thing you may run into is that I believe VA residencies require you to be a US citizen, so a student visa or permanent resident won't cut it. Apart from that though you should be able to do a residency anywhere else. With a US PharmD you'd have to do a 12 week internship in Canada to be eligible for licensure if you chose to move back home as well as passing Canadian boards since there is no reciprocation.
I considered doing the opposite, I loved Toronto and Canada in general and considered moving there after graduating with a US PharmD (American citizen), but the pay difference sucks so that probably won't happen as long as I have loans.