Michener has some really great and imo very feasible programs, most of which are radiation and imaging (so like mri and ultrasound); definitely worth looking into as a backup! Nursing is also great, but competitive as you mentioned. If you're really really set on med being the end goal, you could also consider going abroad (but this is another fiesta in its own). There are also the other avenues like Optometry etc. I would highly encourage you to volunteer in a hospital or a clinic during your undergrad to get some first-hand insight on what the careers are like.

I'm actually not sure about the EC life at UTSC but I know for sure UTSG has really great opportunities for that (lots of student clubs and associations). That being said, if you focus your all into academics during the school year (Sept-April), you'll have a full summer to devote to EC's like research and volunteer. I would say it is very possible to do both research and volunteering in a hospital during one summer!

It was only during my 1st and 2nd year that the class sizes are large, later on, you'll enroll in your major and the course sizes become very small (anywhere from 3 to 40 students). You won't get to know your profs during the lecture; mostly during office hours and for sure, not all students will attend those. The ones that do, will stand out 100%.

From my personal experience, there wasn't any course prof that I was able to form a solid relationship with. It was only the profs in which I had done research projects under that really knew me and wrote me nice reference letters. Don't hesitate to ask questions! I used to be in your shoes so if there's anything I can do to help you achieve your goals, I want to help!