An interline agreement is table stakes though. What would be interesting would be know what they plan to do with it. Do they plan to offer codeshare tickets for onward connections in Canada? Or European SAS codeshares as tags on WS TATL? Do they plan to offer FF reciprocal benefits? EB flight awards on WS?

Fwiw they still have an interline agreement with Air Canada regardless of alliance changes. It does seem like it's increasingly challenging to actually book tickets combining them though. They come up on AC's web site but bookings didn't go through.