Hi, I grew up in Canada, did my BSc there and my MSc there (now at a US school for a PhD).
Your grades/GPA are not going to make you the top candidate but you are also not at the bottom either! The top 3 schools in Canada are UBC (my undergrad), U Toronto, and McGill University. These schools will be more picky -- I know UBC's Faculty of Graduate Studies require a minimum of an A- average in your 3rd and 4th year courses in your field of study. For Physics, this means Physics and Math courses. So, it sounds like you will meet this minimum, because an A- in Canada is 80%. However, in general, I think these choosier schools will want to take the top 1/3 to 1/2 of students, so maybe for international schools, they care less about the GPA and more about your overall standing in your own program. These 3 programs will generally want Canadian students to have an Honours BSc instead of just a BSc, which in Canada means about 10% more courses and a final year thesis, which it sounds like you have!
You will also find that the grades in Canada are different, although some schools are starting to adopt the US GPA system. Many schools, such as UBC, will report your grades as a percentage and a letter grade, although the "real" grade is the percentage. The percentage-to-letter grade conversion is usually a standard faculty-wide and in the Sciences, it is pretty much standard across the whole country.
These grades are kind of a leftover from the UK system (woo commonwealth history!), so a "first class" grade is 80% and up, which means A- is 80%, A is 86%, and A+ is 90%. A B+ is 76%, a B is 72%, and a B- is 68%, etc. going down an increment every 3-4% points.
You have decent research experience and I think overall, you will be a good candidate for the schools you listed. U Toronto is a top tier school but I think you have the profile to at least try and apply. Same with UBC and McGill if you find interest there. Since you have citizenship, this would be great for you in terms of admission -- you won't cost them more and you might even be eligible for a lot more fellowships!
Finally, it is important to know that many Physics programs will admit you directly to a researcher. However, this is more common for PhD programs (UBC's policy is that they will only admit you if a prof says they are willing to fund you for your entire degree). For Masters programs, since it is only 2 years long, you should probably have a pretty good idea who you want to work with but I know UBC will allow their students a few months to decide.
Some programs, like my MSc, will send all applications to all profs in the department. Then, it's up to each prof to decide if they want you, and then they will basically hire you like any other job. When I got my offer letter, it specifically listed which professors were interested in me and that I should choose soon, since they make offers one at a time until all their profs have all their spots filled.
So, I think it would be very important for you to reach out and contact potential professors fairly soon and find out about who matches your research interests. You still have a bit of time, since if they are still the same, the first deadlines are mid-January.