Pre-med is an intention and not a major. There is no such thing as a “premed undergrad stream”.
With the exception of art and musics conservatories, every US and Canadian college offer the necessary coursework required for a med school admission.
It is incumbent on the student to not only earn high grades in the necessary classes, but also to find their own physician shadowing opportunities, clinical volunteering positions, community service site and programs, leadership positions, health advocacy positions and research lab positions. A university won’t do that for them.
There is nothing magical about attending a Top 20 university. Students at Harvard or Johns Hopkins don’t have any special advantage when it comes to gaining a med school acceptance. Med schools are pretty much agnostic when it comes to the name of the undergrad on an applicant’s diploma. Once a student meets certain level of competency, med schools are much more interested in seeing if this individual is good fit with their program and its mission.
Med schools in Canada are much more MCAT scores & GPA focused than med schools in the US. Med schools in the US use a holistic review on applicants where MCAT/GPA is only part of the larger picture.
Also, please be aware there are only about 40 US med schools that will even consider admitting an international students (Canadians are international students). The majority of those 40 only admit 1-2 students/year.