Thanks, everyone, for all the suggestions. I was able to finalize and ticketed my itinerary as follows:
IAD - ORD on UA 1744
ORD - NRT on UA 7938 (operated by ANA)
NRT - KUL on ANA/NH 815
KUL - NRT on UA 7967 (operated by ANA)
NRT - EWR on UA 78
EWR - IAD on UA 1701
The fare difference between this routing vs say, a straight UA from IAD-EWR-NRT (and then NH to KUL) with a return of KUL-NRT on NH and then US-bound to either LAX, DEN, or EWR and a final segment to IAD was a difference of $50. So, for slightly more, I opted for the ANA from ORD all the way to KUL and UA from NRT back to EWR-IAD.