What do you mean by « link your other ow status to your baec »?? Status is not transferable across FFPs. If you want the free seat selection you’d need to enter your other ow number instead of your baec number, but you can’t have both.

if seat has been assigned for free thanks to an expired status, we’ve had both reports by people who kept the assignment without issue and of people who’ve lost it at any random time up to flight departure. It seems like hit and miss.