This is not particularly complicated for AA. I had booked some award tickets for friends that included legs on AA, JL, CX and AS. AA were able to get seats for all sections. I made a number of changes along the way, and was able to do this using only the AA record locater (PNR), with no ticket number. Don't worry, be Happy.
Cheers.
This is way cool when comparing to UA experience!
Do you mean you see seat assignments showing up on your original itinerary?
I do notice the first IB leg now has seat assignment. The rest of the partner segments are unassigned. I dont care much the intra-europe portions but I do want to make sure the BA transatlantic portion to be on the upper deck club world.