I think you meant to say, the problems would be larger due to the argos at bmo.
Regarding the scheduling, and TFC having priority as per lease agreement: that's priority at the time of scheduling. They don't know the possible CONCACAF scheduling (or how far TFC might make it in that tournament); nor the MLS or CFL playoff schedules when the MLS & CFL schedules are set before the season starts. There are also many other restrictions, due to TV schedules, various other schedules for the different soccer teams involved, etc. They could easily end up with a footy game in BMO field 2 or 3 days after a CFL game. Or worse, maybe on the same weekend.
Will TFC then be allowed to bump the Argos out of a previously-approved slot in the schedule? I don't think so.