The undergraduate course of study you pursue should not prevent you (nor automatically qualify you) for post graduate study in teaching.
If you wanted to be a single subject instructor (science, math, English, etc.) in secondary school, then your B.A. would determine which subject you are qualified to teach. Your goal of teaching elementary school means that your B.A. won't deter you in any way from becoming a classroom teacher.
As has been pointed out, if you under-grad grades are good enough, a master's degree education program should have no problem accepting you and turning you into a qualified, certificated teacher.
This is a question that we are very unlikely to know the answer for. You will have to conduct your own research into the various colleges where you wish to study teaching and see what their requirements are. Speaking generally, most colleges will accept people to study to be teachers no matter what their major, as long as you show that you are able to study to a high level.
I'm not sure I understand your question. Is there any way that you can pose it again in clearer language? I will say that no matter what you choose to major it, the ability to write clearly in college will be crucial to success, and there is a special obligation among education majors to write clearly. Good luck to you.
I would have to agree that you should look into the programs the school of your choice offers. The best way to evaluate what you need to take is by examining the program.
I too would suggest looking into the admissions requirements for the specific college you are thinking of attending, but I would think that having your secondary (high school) diploma, solid grades in your high school classes and a good standardized test score (like the ACT or SAT) would be enough to get into college. In most high schools, a balance of courses in the core (English, Math, Science, Social Science) are what is required to graduate.
I don't know the policy at Ontario Teachers College, but my suggestion no matter what is to contact the school (and any others that you're interested in) as soon as possible to find out what courses you need to have, the types of standardized tests you need to take, etc. If you're in the 11th grade, then now is when you need to be thinking about these things, especially if it affects course registration.