Media reporting that pax are staying on the plane until a relief aircraft arrives! That's got be 8hrs or more surely?
I'm sure the Canada Border Services Agency would be totally overwhelmed if asked to process that number of people at CYYR. Much better to await a relief a/c and do a ramp transfer - they will have adequate food and water for awhile yet.
I doubt it'll take that long. In the Swissair 773 diversion to Iqaluit a few months ago they had an A330 out of NYC on the scene in less than eight hours, I think.