There should be no issue between AC Rouge and AC (or any US-based airline and AC, according to their accessibility page). See the blue box on this page: https://www.aircanada.com/ca/en/aco/...ty.html#/home:

I think requesting mobility aid/wheelchair assistance on AC should be possible, do you think a wheelchair would sufficiently accommodate your medical condition? If so, follow the instructions on that link (make sure you click the accommodation best suited for you, which I think is a mobility aid).

It's not published on the website, but if you have a problem requesting accommodation on aircanada.com, I think calling into AC Reservations will help set you up with a wheelchair. Definitely ask again when you reach the airport. Definitely ask again on your flight just before you land in Toronto to see if someone's ready and waiting for you.

This is an AC issue and touches on the services offered by the AC Medical Desk, if you have more questions, maybe the Air Canada subforum would definitely provide more insight

I must have misunderstood the Medical Assistance reply that I got. They have now confirmed a mobility vehicle availablity upon arrival.

Thanks for your assistance.