Thank you fifty_two. I did see your reply earlier but couldn't get myself logged in on my mobile while travelling and didn't have the patience to do a pw reset!

Thankfully you were right, there was no real implication of the message. We got checked in easily once we got to YUL. I am also very grateful to know my quadruple S wouldn't follow me to Europe! I didn't even get an extra swab the whole trip! We did get the seat numbers I saw online, and actually lucked out that both the outbound and inbound TATL flights were not full, and we didn't have to share our row.
It seems every airline has its own quirks and differences. Thanks for making our first flight with TAP a little more predictable.