Friend is flying EWR-YUL-YVR on AC. Checking 2 bags. One bag is for a relative in YUL. 2 questions

1. Can one bag be shortchecked to YUL and one to YVR? I know agents usually don't shortcheck bags because of hidden city possibilities but if one bag is going all the way does that make a difference?

2. Bags have to be claimed in YUL regardless right? Is the claim area for Canada connections and regular arrivals the same? If so can he claim both bags, put on on the connection belt and hand the other off to relative? In Toronto they are the same but on the AC website it implies that the lines are different by telling you to follow signs to Canada/US/International connections.

Thanks!