I had some time to think about this (as it is really an interesting situation), and thought I'd share a few cents, as the LATA probably doesn't cover all the details.
A new owner is under no obligation to continue renting out (
http://www.ltb.gov.on.ca/en/Key_Information/STEL02_111677.html... If the LATA doesn't specify what "for own use" means, the new owner might even be able to say they want to use the condo as a storage space or something other than moving in themselves). However, I think you would be the one responsible for providing the 60 day notice, since the rental contract is in your name (whether the new owner wants the tenant out before closing or many months after).
Therefore, I would think it's in everyone's best interests if the tenant is informed that the property is being offered for sale (at least 60 days prior to closing), and for the new owner to sign a rental agreement with the tenant (after finalization of the agreement of purchase and sale, and at least 60 days before closing).