I feel like I want to type out my experience here for closure/posterity and anyone else going through the process in future years. I found the process confounding and frustrating. I had one firm cancel a second interview with me after they asked me to reschedule it an hour before it was supposed to happen My takeaway from this is if you are meeting with a managing partner and other heavy hitters on the third day and you have had two other good days of interviews you had better kill it. I felt like I totally hit it off with the managing partner and did a good job with the head of recruitment but was just a little flat with one really important partner on that third day. I was told I was extremely close to the cut and that the difference probably came down to having less insight into the process from being from out of province (this feels like pablum but I suppose I might as well take it). That said, HUGE thank you to everyone here though because I would have been clueless without all of you. My mistake as I understand it was that if a firm is telling you explicitly that they are very interested in you and giving all the right signals and telling you you are doing great it should not be taken at face value. The other thing that I would do differently is I would twist both my answers to questions and my questions in order to address what may have been holes in my qualifcations even if the interviewer doesn't ask about them.
All of this said, I'm trying to see this as a blessing in disguise because I think I may have been aiming at Bay Street for the wrong reasons and it is very possible I would have hated my life if I had been successful.
So thanks again to everyone here (especially you power users) and if any of you Ontario students are generous enough to loop an out-of-province person in on some of those non-oci summer opportunities (the person at the firm who let me down easy told me these exist) I would be eternally greatful and do my best to repay the favour.