I'd say that (2:45 hours) should be sufficient time, even if it's cruise season (ends in late September). Allow 4 minutes to walk from a/c to luggage claim, 15 minutes for bags, 6 minutes to walk to U.S. terminal, 15 minutes to check in, 15 minutes for ICE/BCP, 10 minutes for security, 7 minutes to gate. It'd help if you have printed BPs ahead of time and filled out the U.S. customs forms (shaves a few minutes here and there). Nothing practically available to them (or to you) really saves time at YVR other than check-in (normal elite stuff) otherwise. What could get interesting is if their flight is cancelled and they have to travel on the following (hour later? flight). Still should be enough time depending on how long it takes to get reclaim bags.