Just booked a Pacific Circle via AA. SFO-HKG-PER-MEL-SYD-DFW (originally included DFW-SEA but that put me over 22K miles and would have added $2000 to the fare. Instead I booked a separate DFW-SEA in coach and upgraded with miles. The cost was about $200 plus 15K miles).

Now to the question. What is the best way to get seat assignments? I was not very impressed with the AA agent, so decided to try later. She said something about CX not assigning seats in advance.

SFO-HKG-PER is on CX with SFO-HKG on AA codeshare.

PER-MEL-SYD-DFW all on QF; SYD-DFW on AA codeshare. Is it possible to manage seat assignments online via the QF and CX websites? I assume the AA record locator will not work.

Thanks for your help.