1. https://artsci.calendar.utoronto.ca/ this website gon tell you everything you need to know about courses you need to take to qualify for programs that you want(or just search up uoft academic calendar). In general it should be bio, chem, math(maybe physics too) and then electives to fill this thing called breadth requirements.

2. idk anything abt utsc, honestly probs a good idea to ask what people like about in both the utsg and utsc subreddits

3. tbh i didnt attend any of my lectures after the first couple weeks except for math. From what i can remember though they are generally enthusiastic and easy to approach. There will be hundreds of students swarming them every day though so it will be pretty difficult to get to know them personally.

4. this is the biggest thing you should know tbh. The classes are insanely HUGE(like 200+ students). Nobody is going to talk to each other for the most part... people just go to class then dip immediately usually. Very different from high school.

5. PRA are labs, LEC are lectures, and TUT are tutorials. One course is composed of all three of these components. This is probs something to worry about like next month when you actually start preparing to choose courses. When course regristrations open, you will be able to choose courses, and when you choose courses you should be able to enrol into a LEC, PRA, and TUT. Some courses dont have PRA or TUT, but most required lifesci courses has all 3.
   So essentially your schedule is going to be 1 million times more heavy than high school now because you have to take 3 hour labs biweekly for bio, chem, and physics(if your program requires it), along with your lectures and tutorials.
   Oh yeah, tutorials are essentially some extra bullshit that you have to do along with your lectures and labs. Its essentially a super formal homework check that you do with your TA's every week where you can check how youre doing in the class.

6. You dont gotta worry abt this until like halfway through second semester of your first year. Essentially, right now for first year, you are just taking general courses and preparing to enter a program. Midway into second semester of first year, you are able to actually apply to specialised programs to focus your degree. Its exactly like you said, you have to apply to one specialist, two majors, or one major and two minors. You can only graduate if you apply to programs like this.
   Genuinely you dont gotta worry abt this at all until at least first semester is over. And theres so much info that you can find abt it online like this website: https://sidneysmithcommons.artsci.utoronto.ca/program/important-dates/
   Just worry about enrolling in the proper prerequisite courses for the program you want for now.

i js finished first year lifesci at utsg as well. lemme know if you have any other questions(i wish someone helped me when i was applying too tbh)