Oh, that's pretty good guaranteed funding, and I'm sure if you put a good effort into the TA/RA positions it wouldn't be too hard getting positions for the second year...I know that good TAs and RAs are fairly hard to come by.
I actually haven't looked into OGS at all...I was just planning to apply for SSHRC in the fall. Probably should of looked into that!
You seem like you are on top of everything and have experience/grades needed for the program. I wouldn't worry too much about getting in if I were you. I don't think admissions is too competitive?
For aesthetic reasons I wish they had kept the previous name or changed it to something else. There's already an MPH program at Waterloo and so many MPH programs in North America that the title really loses its uniqueness and no longer indicates that its a research focused degree.
edit: BTW, I saw your post about why are MSc programs recommended over MPH. It's because some MPH programs have a lamentable reputation for being degree mills...taking in a lot of students and charging a lot of $$. The MSCs are generally more competitive, provide better training, and are funded through research and taships...all indicative of good students/programs.