Originally Posted by
seigex
Check in online isn't required, but if JAL will check you in through on OZ, then that works and you don't have to worry about getting your boarding pass in Japan. Otherwise you can go to the OZ counter in ORD and see if they are willing to check you in for the NRT-ICN leg. I've had luck with this between UA and ANA, but haven't tried with JAL and OZ.
That said, given that you have a newborn, and have to wait for your gate-checked stroller, that might create some issues and that would be enough for me to go for a later flight.
Good luck whichever way you choose!
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.