Hey! I'm a cegep student in 1L at McGill. I think you have a chance. Even though your R-Score is below average, you have rich and interesting ECs. Concentrate on writing a compelling PS and getting strong reference letters if you want to solidify your application. I encourage you to apply. The best thing that can happen if you do apply is that you get in. The only thing that can happen if you don't apply is that you don't get in. So you have nothing to lose by trying! And besides you should get into UdeM with your grades. Good luck!