Thank you both so much. I was just on the official Canadian gvt website, and it states the info below. Whew - this has been challenging to keep straight!
Entering Canada by land or air before embarking on a cruise
You must complete your ArriveCAN submission before entering Canada, no more than 72 hours of boarding your flight or before entering Canada by land.
If you’re flying in to join a cruise immediately, enter the address of your terminal.
If you’re not joining the cruise immediately, enter the address of your hotel.
You must also submit a second ArriveCAN submission no more than 72 hours before boarding the cruise. This applies even if your second ArriveCAN submission is within 72 hours of the first submission.
Upon your entry to Canada by air or at a land border crossing, the border services officer may notify you that you’ve been randomly selected for a mandatory arrival test.
Mandatory random testing is part of the Government of Canada surveillance program to track the importation of COVID-19 virus into Canada, and identify new variants of concern.