I booked a one-way LAS-OGG via phone and booked an extra seat. I see the same thing, the seats are attached to the reservation but you wont see anything in the app. I also called and was told it was no problem. Time will tell LOL, my flight is in December. If we go.

OP, if no one told you, I was advised I cannot check in online or using the app. I have to check in at the airport. If you all are on the same res, you will probably have to do the same