I can't believe MU has beaten CA in terms of providing service to Toronto. Several years ago, I heard some stories about CA planning to restore service to Toronto (in which case, I'm guessing that the flight numbers would be CA993/994), but those plans have evidently not come to fruition...
Another Chinese Airline has been rumoured for a long time. Not necessarily the one I would have guessed but it seems to be happening. I too was expecting Air China to resume. If the business links and tourism continues to grow, direct service to a couple other centres from both YVR and YYZ will show up within a few years.