Originally Posted by
PTahCha
UA will not be able to issue boarding passes for ANA flights. The passenger can use the connecting corridor and walk to Tom Bradley terminal and check-in at the gate, or exit security, take the interterminal bus to Bradley terminal, and check-in at the ANA desk. Make sure to present baggage tags so the check-in agent can enter the baggage tag information into their system.
That's my read as well. I find advance boarding passes fairly overrated; ANA would probably want to reprint them anyway, and they'd definitely want to know the bag tag numbers. The only reason I can think of to worry about this is probably the right one: if OP's fiancée were trying to access the *A lounge prior to ANA staff arriving, I'm not sure she'd be able to get in with just a printed itinerary.