I think that your options in Canada are very likely for admissions and great universities. I would think that admissions to UBC is pretty much a safety although your son’s guidance counselor would know better than I.
I understand why you would consider Stanford and Caltech. As a Canadian who graduated with a masters from Stanford decades ago, I think that finding a job in Canada would have been easier with a degree from one of the top Canadian schools (including any of the four you are considering).
My understanding is that Stanford and Caltech meet full need for international students. As such you could run the NPC and see what it says. Your definition of “need” will not necessarily match theirs.
I would be surprised if you would get any financial aid at all from UC Berkeley. I do not think that it is worth three or four times the price of UBC or Toronto unless US$67,000 per year is easy for you. I am not as sure about financial aid from Washington but again I do not see the reason to spend that much more compared to the price of the Canadian universities that you are considering.