I have been summoned? Also, nice to see me responding in a thread from 2013 without being a jerk. Hey, there is some progress right there!
Getting in law straight from CEGEP is a tough sell at McGill. You need to have 30+ Cote R AND some pretty good extracurriculars, while also working closely with professors for your reference letters. Get involved in something that you're passionate about, whether it's being in a leadership position with your student council, volunteering (in a meaningful capacity) at a charity/group, while maintaining high grades.
From what I recall, the CEGEPers while I was in law school were all involved in a leadership role in a club and had some pretty good volunteering roles. A few model UNs, some had their own businesses, others were involved in organizing food and clothing drives, etc. Less impressive than the undergrad admits, but it's a different category of applicant. That said, it's fairly competitive. You also really need to nail the "Why law" and specifically "Why law at McGill".
My advice to the OP remains the same - it's not the end of the world if you do an undergrad degree first! The trend at the UdM seems to show more people are applying to law with an undergrad degree rather than just straight from CEGEP.
It probably won't affect recruitment that much, you were already not competitive for firms that are looking for academically strong students. On the other hand, there are quite a few firms that care far more about fit and drive than about grades.
Diplock has many posts on this topic. You are permanently out of the running for grade-sensitive jobs. You can still get jobs that are "subject sensitive", but you need to signal some real interest in that area - a good grade in the relevant black letter course, relevant clinics+mooting+externship, actually working for a practitioner, or having some truly marketable skill like a language.