Great idea on back up locks. I think as of now you still have to show proof of vaccination status. Hoping by Aug. all the Covid hassles are clear.Make sure to get your rifle re-importation paperwork done early and keep 2 copies in waterproof bags.
Bring spare locks for your gun case in your carry on; I’ve had my locks cut off on 2 trips to Canada. It was very disconcerting to claim my case in Edmonton and Calgary with cut locks inside along with a TSA tag, but there was nothing missing either time.