Married segment upgrades will clear based on availability of each individual flight. You can check this by doing a search per segment in expert mode to get an idea of availability on each flight.

It’s the “direct” flights with one flight number over one or more stops that generally require through availability for an all or nothing upgrade. Assuming each of your segments has a different flight number you should be good to go pending availability in PZ.

If you end up clearing the domestic segment but not the overwater segment UA should redeposit the GPU back into your account.