I know NWs entire narrowbody fleet has no IFE.
No, all of NW
's B757 and 50 of their A320 have IFE systems, but NW
doesn't utilize them on domestic flights. The A320 serving NRT
are among the 50 with IFE systems and yes, NW
does utilize them. Seat pitch is exactly the same in economy, although the planes have a watered-down WBC.