When I arrive at Pearson where do I go. Do I go to internantional departures or Domestic departures.
You need to go to the domestic departures area.
Once my luggage is checked will I have to see it again or do I have to retrieve it and re-check it at yvr.
Yes, you will need to retrieve your bags, pre-clear US immigration, and drop off your bag again. See
the YVR website connections guide for details.
If I have to retrieve my luggage at yvr on the way back and re-check it that is going to make a tight connection. If I miss the connection will AC have to put me on another flight or is it my problem.
You have plenty of time on the way out. You should be OK on the way back, but even if you miss the 11:20 departure you will be put on one of the many other flights to YYZ. At worst you might be a little delayed.
It looks like this will be one of the best planned trips of all time!