I am Silver on AB (OW Ruby) and have an upcoming trip with BA.

However, I found out that I am earning way more miles with BA and since it's a long haul flight I want to credit the miles to my executive club account (Blue tier.)

With OW Ruby I can get free seat selection 7 days before departure and business class check-in though. Do you know if it's possible to edit my FF number in the Finnair website one week before so I can select seats and then add again my Executive club number?

Also, in order to use the business check-in counters does my status need to be in the system or is it enough if I just show my AB card at the agent?

Thank you!