Admissions at highly ranked universities in the US will understand how your grades compare with others from Ontario. I don’t, but will assume that you are relatively close to being at least in the top 1% in your high school, or of students from Ontario. Certainly your grades and your SAT score are very good.
With this, you can figure that about 80% of applicants to your reach schools in the US will have stats that are similar to you, and will also like you have ECs that are very good. The acceptance rate for international students might be closer to 2% (or slightly less), and this will include at least a small number of legacy students and athletes. As one example, Harvard frequently has quite a good hockey team – way better than you might expect for a school that does not give athletic scholarships. Some of those Harvard hockey players are probably Canadian and they might have benefited from a slight admissions edge over those of us who are not athletes.
A bigger problem is that as an international student you will most likely be required to return to your home country after graduation. At least in my experience as a Canadian graduating from MIT many years ago, it seems that Canadian employers prefer to hire graduates from the excellent universities in Canada.
I do however, know several students who got their bachelor’s degree in Canada, and who then got either a master’s degree or a PhD or both at top schools in the US, including schools that are on the level of the schools on your reach list (eg, Stanford and Princeton).
Plan on spending at least US$400,000 if you want to get a bachelor’s degree in the US unless you qualify for very good need based financial aid, keep the exchange rate in mind, and do not forget to also budget for any graduate degree that might be likely given your major. A bachelor’s degree in Canada plus a master’s degree at a top university in the US is likely to cost less in total compared to just getting a bachelor’s degree in the US.
Not all of them are need-blind for international students (eg, NYU considers need for international students, at least according to a quick Google search just now).
Your other points are very accurate. If the students needs aid then they better apply for it. Admissions is tough for international students at the top universities in the US.
I do have to wonder whether recent political controversies in the US will impact the number of applications from Canada, although some of these controversies might have occurred after applications were due.