I got my Canadian ATPL in April. I had to get a medical, take a written test (basically a differences test/ instrument knowledge) and show them many documents proving I passed my PC and type ride(that covers the practical). If you have numerous types they will charge you $30 each to have them included on your certificate.
MOT will not accept a US medical, you must have one yes, but you will need to go to a Canadian DR. for a Canadian 1st class.
Of course as previosly Noted, you need to have the legal right to work in Canada.