Hi Kid_X. First, I'd like to tell you about Aircrew Selection.
Aircrew Selection is a for the CF to judge of your learning capabilities. Aircrew Selection is a little simulator in which you do 4 sessions if I remember correctly (4 years ago...) The computer tells you what to do and you have to do it. What they ask you to do is straight and level flight, turns, climbing/diving turns and small procedures. The last session is a combination of all you learned. The pass ratio is about 20-50% (on my serial, 2/10 passed for pilot and 9/10 passed for Air Nav). Aside from the Pilot Selection, there is also the Air Nav selection ,which is a written exam. A lot of questions (Maths, spacial orientation, chart reading, etc) for little time.
After Aircrew, there is the medical, in Toronto but that shoudn't be a worry if you're in good shape. If you go to RMC, after the 1st or 2nd year, you should be slotted to go on Primary Flight Training, in Portage La Prairie, Manitoba (a hour west of Winnipeg). This is still a selection course and it also evaluates your learning abilities more than you flying skills. Usually, a few fails that phase. (6/24 on my course). The biggest problem on that course I think is the "summer break" attitude. People are going in Portage after a year in school and think PFT is easy an is a joke. Most of these guys fail... Yes, Portage is fun but you have to work on your primary goal first, becoming a pilot.
For the recruiting standards... Seriously, if you're not a potatoe couch, doing no sport, and nothing outside school, and you have good marks (70+) you should make the cut. I know people that had a 65% average in school that are in my program. But I have to admit that most of the people in my class had 85+ averages in school. The other people (those who had lower averages) failed Mech Eng (usually, the average drops 15-20% here) I think the interview is a big part of the selection. This is YOUR chance of telling them WHY they should take you. Take advantage of it!
As for the revoking of the offer, well from what I understood during my enrolment process, if you have a conditional offer and pass school, you should be able to accept it. Mine was conditional to the success of my studies.
If you have any other questions, just let me know eighter here or by Private Message.
Max