Looks like LAX-NRT is showing 3 seats for sale although it appears that there are 6 unassigned seats. Could potentially be an agency holding some seats that are not yet ticketed or an agency that has not assigned seats so the number may actually be 6 open.

SFO-NRT and PDX-NRT look like there are 2 available for sale but really probably are 3 unassigned seats. Usually they block 2-3 seats in rows 5 and 6 center section for pilot rest but people end up getting those seats at the airport. I would think PDX-NRT would have a great shot at clearing with an SWU at the gate though....

Looks like all the flights to NRT this Saturday are quite full but I would think you have a pretty good shot as a DM using an SWU to snag one of the last seats on any of the 3 flights you listed. All 3 airports have pretty great DL agents (SFO and PDX are two of my favorites) who won't put a NRSA in an empty seat before a DM or PM using an SWU.