Thanks for the input everyone. So:
- I am already ticketed with BA.
- I couldn't ask AA anything because they flatly refused to talk with me about the booking since it was made with BA.
- I asked BA if they could find availability with the AA codeshare and the answer was no D class available.
- I don't think it is a marriage issue because I am landing in LAX 5 days earlier and leave SYD 5 days later. On the other hand, the existing booking has two segments, which I will remove, from LAX to ICN via HKK (same day) so maybe that is having an affect.
- I don't really want to go to SFO as I need to be in LA all that day and the stress of a connecting flight is getting too much to deal with.
- I really don't want to fly on the AA flight on a 777 (despite the wonderful AA service).
I think that covers everything.