Assuming on time arrival 2:40hrs is more than enough to collect baggage and recheck in ARN. You should be at the check-in counters LATEST 1 hour after arrival at the gate. Probably way before that. I guess more like 30-45 minutes.

EBG will help at the bag drop and to get back airside via the security fast track. So, very useful. The *A will not do much, the priority tags are blissfully ignored by the baggage handlers at Scandinavian airports