Some people here talking over each other. For clarity:

* The flight is far enough out is a scheduling change, and you are entitled to either a full refund, or accepting the change. Accepting the change, there is no delay compensation, it's not delayed, it's changed.

* Knowing you are entitled to a full refund, AC will assist in options, both on the inbound and return. They may only offer equal or less expensive options, but would wave fees. You can push for reasonable (if more expensive) options, but you will need to be prepared to ask for those reasonable options by name.

* If you proceed with flying (with the auto change, or manual change), the reservation *changed*. Any day of issues would not nullify that, or compound that; day of rebooking (or compensation) would be based on the accepted itinerary, not what was booked first.

* Air Canada will take care of you (eventually, and with effort, changing your return flight, even) if there are delays and a missed connection in YYZ. Trying to outsmart them (booking from the island on the racoon) would be unwise. AC would not GAF about that flight, and if you miss it, your boned. I'll offer up that if there is snow on the runways, there is also snow on the 401. As always, if being late means missing a wedding, funeral, or million dollar sales meeting, fly the day before.