Has the OP thought about the possibility of buying an EXST in FC? I haven't done the research, but AA allows you to purchase a second seat on the same flight for comfort or other reasons. The ticket name will be LASTNAME EXST and the PFC fee is waived. When boarding, OP will scan both boarding passes.

The potential problem is I am not sure if you can purchase a second seat that is not adjacent to your original seat (in a different cabin actually in OP's case)