Thanks so much for the speedy reply!

So I won't be able to check-in online beforehand??

Worried that this might be bad in terms of seat allocation....
Although on my expedia reference and when I view my booking on Lufthansa I already seem to have seats allocated - do you think I'll manage to keep these ones?

I just tried to 'manage my bookings' on aircanada.com and it says it can't access it because it was booked by another website.... doesn't seem I'll be able to check-in online there...