When are you travelling?
I am waitlisted in "A" class for HK-LA next week (July 1st) , protected in J, and CX still has 3 F class seats left. The Marco Polo Club has sent a telex to "control" and the res agent seems to think that even one week to go - it's too 'early' to tell. Basically I am getting a 'special' first class ticket on Cathay. If worse comes to the worse, I will go in J as I have already booked on that one. But as one knows, the preference is for Betsy seats - and CX food!
The control and releasing of seats won't come from AA - it will come from CX. And if CX won't even confirm to their own elite members, think of what chances other partner airlines will do.
My advise is to call CX's res and tell them that you're an Oneworld Emerald member, and ask if they can send a message to 'Control' to release that one seat for you. It won't hurt to at least try. But chances are, you might have to wait till literally a week before you travel. And oh yes, having issued a ticket and advising CX of your ticket number helps a lot too. CX is very adamant about getting tickets issued. If you've already issued your ticket, they might be more willing to release that "A" space.