No, MBAConnect is a network admitted students gain acess to. That's why people keep asking about its count, so that they can have an idea of how many people are already admitted and how many spots are left in the class. If you check the waitlisted thread, you'll see people asking about it all the time.
I think it's safe to assume there are less applicants in R3 when compared to other rounds, but there's no way to know the exact breakdown. Also, GC is an indicator of how many applicants are there, but we don't know what part of the applicant pool is actually active in this forum. So it's just a guessing game. In the end, less competition would work in your advantage, right?
Good luck!
bizwiz