Short answer is yes, Approved Check Pilots (ACP's) can conduct rides where the medical has been revoked. See here:
Approved Check Pilot Manual. I can't speak about the DFTE's (those are the examiners who do licenses here in Canada, but my guess would be no as you'd likely need a current medical as that's all on-wing examination).
However, here is the catch:
Where an ACP’s medical certificate (Medical Category 1) expires or where Transport Canada has suspended or refused to renew an ACP’s medical certificate (Medical Category 1), the ACP may obtain authority to continue ACP duties in a simulator only provided an application for simulator-only authority is submitted.
That implies that you require the delegation before you can be moved to simulator only status. Unless you currently hold a Canadian license, you might be out of luck as to get the delegation you need a current license and, as you know, a current license includes a valid medical.
Furthermore, most (not all) ACP's in Canada are employed by an airline or other operator. There are companies who hire contract instructors and ACP's, but a call to Transport Canada is in order, to see if there can do some behind the scenes dark arts for you before you talk to an operator about sponsoring you for the ACP.