This should work fine. For TWOV, China doesn't care whether your seat on the flight into the country is confirmed, it only cares that your departing seat is so. Assuming you fly that exact routing inbound (the NRT stop is critical) on 11/30, your 72 hours now begins about 3 hours later, Monday 12/1 at midnight (00:01). Your confirmed flight on the refundable ticket must be no later than end of Wednesday, and can't route directly back to Japan. If you get a non-rev seat back to USA, it also can't route back through Japan.

If you are able to procure the non-rev return, my advice is to hold off refunding the confirmed ticket until the last possible minute--as in, you're at the gate and the plane is boarding.

While I obviously haven't personally done this, I do know firsthand of non-revving airline employees who have successfully used this strategy of the refundable Plan B ticket to maintain eligibility for TWOV. Though the routing was from SE Asia - China TWOV - USA. Principle is the same.