Thanks everyone! I got an email back from St. Lawrence and they said they will go by my highschool admissions only, then by my post-sec grades if necessary. Their entrance average was only 80% last year, so I'm not as stressed out about it as I was before. She also said that they don't offer alternative admission, but there's generally plenty of time between their 'rejection' offers and their final enrollment dates for pre-health, so if I don't get in, I should just apply to that.
So it's nice because I also don't have to spend a flipping fortune sending in my uni transcripts unless they ask for it
Hopefully I get in! Like I said, I'll take the pre-health if I don't get in, but there's no sense to me to just enroll in it and spend a year doing it when, by all the college's accounts, I don't need to. I'm a 'mature student', but I'm in school and still have the qualifying OSSD credits, and apparently that makes the difference.