besides the 50-50 gpa and ECs split, does ottawa have a post-interview formula? if not does anybody know how they handle acceptances post-interview.

Stop asking these specifics. They're useless information.

Get as high an MCAT and GPA as possible. Try to get a variety of experiences; work, volunteer, research. That's it.

Here is the paper: you'll need to access the full-text to read the interesting detail...

http://www.ncbi.nlm.nih.gov/pubmed/22914514

Note this was in 2012...could have changed now

But as it stands from then: the invitation to interview formula was 60% Academic record (mainly GPA, partly pubs and awards)
21% Letters of Reference (lol)
10% Autobiographical sketch
9% Personal essay