Choices

Hey guys I’m not sure what category this falls into so I’m just going to get right to it here. Note I’m a Canadian applying from Canada.
I was admitted to all the universities I applied here in Canada (except Waterloo, results are coming out this May since I did not apply before the first deadline) for computer science or engineering. Currently my top choice would be U of Toronto Engineering program. I only applied to UBC, Western, McGill, and Waterloo. My parents are not interested in me attending any university in Canada other than U of T or Waterloo.
I also applied to several universities in the US with not too much success. I got admitted as undeclared into UCSD and waitlisted at Brown. These are the “best” results. I’m starting to realize that I’m considering transferring next year as I’m not too keen on attending U of T for the next 4 years.
My question is would it be easier to transfer to transfer friendly schools (such as USC, Notre Dame, Vanderbilt, and a few others with higher acceptance rates) as an undeclared major in UCSD or as an engineering student at Toronto.
There is also the fact that many people consider U of T as hell for your GPA (not too sure about UCSD). Many very smart people I know struggled to keep a normal GPA.
I also think that if I did attend UCSD, I would be able to apply to transfer to UCSD engineering/computer science (which I heard is extremely competitive) from undeclared at the same time (is it possible to apply transfer to another university and also within the university?)
What would you advise I do, why?
If I do end up at U of T for 4 years would work or graduate be a possibility in the US?

At UCSD transfer students cannot do a further internal transfer. Also, at ND and Vandy transfer admission is more difficult than freshman admission.

U of T engineering will be hell for your GPA, but as long as you survive, you should be fine for getting a job in the US. Your citizenship status will be a bigger hurdle for that. You should be fine for getting into a US graduate school from U of T. But again, many of the research grants/fellowships require US citizenship.