OP can transfer SPG Starpoints into AsiaMiles and apply for an upgrade if on a CX ticket. As has been pointed out, Aadvantage miles will not help in this regard. OP can choose to route JFK-NRT-BKK on AA and JL, and upgrade with Aadvantage miles on the JFK-NRT route.
Just a nitpick, but UA miles can be used to upgrade LH flights, and if UA ever returns to the *A Upgrade Program, upgrade on select full fares to the next cabin on the airlines that participate in the program.