Phoenix is run by the same guy who had other flight schools in the province of Ontario that were shut down. More info as to why here:
Phoenix Aviation Academy
All other 3 schools you mentioned are well established and reputable.
(Note - Confed caters more to the "bush" side of things - you'll come out of there with a float rating, but not a multi-IFR. Not saying you can't easily add a MIFR somewhere else after, like at Cornwall Aviation, but just as an FYI.)