Your AAdvantage Gold status gets you only 1 free checked bag (iirc). AA TATL flights already get one free checked bag. So there seems to be no purpose to this benefit.

Suggestion:

• Don't put any FF number into the AA reservation.
• Fill out missing miles request on Alaska for the TATL flight
• When the domestic segment is declined, request it in AAdvantage

Remember, you don't officially get ANY miles for a BA-coded AA flight. Traditionally, they seem to post, but there are recent reports that they aren't allowing this anymore.