Unfortunately no. You have to go through a MLT program to write the exam. There is no other way.
Those would be included under various branches (Ie. Urine microscopy is in Chem and Diffs in Hematology). Immuno-Sero would be in Clinical Chem and Microbiology
Those are the core areas but there is also Safety, Professionalism, QC etc. Check the exam blueprint on the CSMLS website.
It's very different from University Chemistry. Much more applied and more in terms of how it works within the body.
Also I think everyone had some sort of job after graduation.
Placements were lottery system based on what was made available for that year. They try to place you at just one lab but sometimes it's not possible with what they have available. I was at Gamma Dynacare and The Ottawa Hospital.
I'm not super familiar with all the US terms but we are trained in 5 disciplines and can practice in all. You don't really become a "generalist" or "specialist" except through training. Most labs you are hired to work in a certain department if the lab is big enough (which most are) or you are in core lab (Chem, Heme and Transfusion usually)
Definitely need to have some math abilities to calculate out some formulas but don't need calculus or anything :)
You should definitely upgrade your highschool marks. I think you can do it for free/cheap through SLC.org but I would say most of my class had at least an 85% in high school and I know it's become more competitive in the last few years.
Depends where you work but most likely never. You'll have to do it in school to be trained as its part of your competency as a tech but as long as you don't work in a very rural hospital/lab you should be ok!
If you want to advance having a B.Sc, especially in Canada in important. Most new techs now have a BSc so you'll need it to be competitive in the future. I would say it's something you can get while working in the first few years as a tech though!