Hi,

All of those segments are part of the same itinerary right (you didn't book two seperate tickets, one for Toronto-Vancouver return, and the other for Vancouver to Hawaii)? If so, then Air Canada should be able to check your bags straight through to Hawaii, and they are responsible if you miss a connection. However, on your way back you will likely have to go through a customs check in Vancouver (first point of reentry to Canada) and then bring your bagage back to the Connections desk and get it put on the next flight. Again, if this takes too long and you miss a connection they are responsible for putting you on another flight.