The current ones I see listed are provided through Chase Bank but they seem to be US focused. Perhaps you could contact Chase Bank and see if they have something? I am pretty sure though that the US Chase one does not have any foreign transaction fees... maybe that would work? Reach out to MR directly and see what they have to say if nothing else.
I live in Montreal and have the Chase Marriott points credit card and have received no such notfiication. That would be very surprising if it were true. If they do cancel the points or the card, switch to the Starwood points credit card available in Canada.
Just to be clear, this issue relates only to Halifax (UK) cards which are ceasing to operate. Marriott say a new UK card will be launched in due course once agreement with an alternative provider has been finalised. No details or date have been indicated yet though and it is very disappointing that the change of provider could not have been completed seamlessly with no gap! There are several forum posts which discuss this issue further.