Were you flying direct to a Canadian airport? For those flights, pickup is four hours ahead and you cannot use the Resort Airline Checkin, so your info wouldn’t necessarily apply to the OP.
OP, my advice is to leave your bags with bell services on checkout day until about 30 min before your bus time If you want to go to the parks or hang out at the resort pool. Be at the ME bus stop (not the same one as for the parks) with your bags already reclaimed from bell services at least 15 minutes before your bus time. Your bus time will come in a letter to your room the day before, and it will be roughly (but not exactly) 4 hours before your flight. You give that letter to the bus driver when he arrives, and he loads your luggage under the bus. You get your luggage back from him at the airport, then go upstairs to the main level to the WestJet desk (which is very close to where the bus drops you off on the lower level) to check your bags and such. The security checkpoint is just to the right of the WestJet desks. It’s very easy, just a bit time consuming.