no la. they have to depends on the grade 12 results. and for visa student they ahave to get certain scoresf or TOFELs result before confirming the offer.
definitely tuition will be cheaper lar. visa student's tuition is around 3X the $ of local student.
you should also consider all the expenses to see if it's cheaper to study in US or UK. but personally i think it will be cheaper going back to Canada to study university, if you have family over there.
YES, citizens have a better chance to enter because for each university, they can only accept a certain percentage of visa students. Say they can only accept 20% visa students, then all visa students will have to compete that 20% quotas and the citizens can compete the 80% spaces.
I was a visa student when I entered university here in Canada. My average was 94% and I can only get into Industrial Engineering (my 2nd choice), where as my classmate, a canadian whose average was 87%, she got into Electrical Engineering (my 1st choice). I could only get into EE if my average was at least 96%.