US/Canadian college for an International student?

I don't know about all those certifications, but University of Toronto definitely has the prestige factor for Canadian universities. Although, University of Waterloo is by far the most prestigious Canadian university in my opinion.

My thoughts were that McGill is good for law, McMaster is excellent for Health Sciences, Brock is for athletics, and Waterloo is for computers and business. Correct if my perceptions are wrong though.

A major is just the program you're specializing in (eg. Graphic Design), whille a Minor would be just a thing on the side (eg. if most of your electives are something like, Linguistics, then you might be eligible for a Linguistics minor.)

How ya doing, buddy?

Visavi explained credits neatly already but here they're "units".
Those are designated by the course requirements on an online undergraduate calendar where you can look up info that is specific to whichever discipline you wish to specialize in.
Electives which you can make up your minor with will definitely total up to less units than those which are compulsory for your program.
Overloading by a certain number of units is going over the amount of units you normly have to complete.
This is probably obvious, but more units = more tuition expenses

There's nowhere I can't reach.