It's called NRT slots, and contractual routes that Air Mike holds which makes it a valuable asset. Air Mike holds a separate operating certificate, and therefore can be sold separately from the rest of CO, if needed.
I'm sure that AMR could pick up NRT slots without having to get Air Mike from CO. You have to remember that AA has a lift problem. If they acquire these slots, they are going to have get some lift to fly them and AA is short of 777 lift as it is. So I presume we are going to see AA going 772ER shopping or maybe (although highly doubtful) A340 shopping to get planes to fly these routes.
I still think that AA is going to make a play for NWA Asia service. I don't see them letting Delta get NRT fifth freedoms and lots of China service without a fight.