Same situation - one phone last scanned as arriving in Korea, the other phone clearing customs in Alaska. These both involving upgrading 7 Pluses on the IUP.
Just spoke with Apple to ask if I could go to the store, get new phones apply them to the IUP and return the UPS phones when and if they arrive. They still show Nov 6 for both on their systems. They said I would need to wait until after Nov 6 and if the phones did not arrive by then, I could go to the store and do everything. But they said it would involve resetting carrier eligibility, applying for a new loan, returning the old phones.
The other possibility might be to buy two new ones today on IUP, transfer phone numbers from the 7 Pluses, then when the UPS delivery arrives, take those phones to the store. The trick would be to then replace UPS delivered phones on the IUP with the new ones. I'm not sure if this can be done. The more I think about it, the complications might not be worth it.