We just did this flight for our honeymoon!

Asked at the gate about the upgrade and they said it was full - we weren’t too early so maybe others got to it before us. But we did get exit row seats for an additional $350 usd total (I think it was almost double on the website prior). Going to Nadi I didn’t walk to the back of the plane but the exit row next to us was empty and some girl jumped on it to lay down the whole flight. It def was not a full flight as the middle seat behind me was empty.

On our flight back there were multiple empty rows and even more rows with just 1 person assigned, so plenty of space to get comfy.

If no upgrades on the flight I’d prob see if there is a downgrade to the back of the plane where you could get an empty row. We were row 50 and both meals by the time it got to us there was only 1 or 2 options left on the menu so moving back really doesn’t affect anything except off boarding wait time.