Originally Posted by
CPH-Flyer
There is the tiny little difference that UA and NH are JV partners across the Pacific and in the same alliance in general, whereas JAL and Asiana are in different alliances and don't have any form of collaboration. JAL will most likely not be issuing a boarding pass or checking through luggage to a OZ.
Yeah understood, that's why I qualified it with if. OP did mention they would interline, but I wasn't sure if that was just an agreement or if they'd check you through. I didn't go through with my JAL-OZ flight, so I never had a chance to check.