That can be tough. Lots of guests make earlier reservations and drag out their meal so they can see the fireworks from Ohana. Then that leaves guests with later reservations prior to the fireworks standing in the lobby waiting to be seated. There is a big exodus of guests right after the fireworks are over. You might make a later reservation and watch the fireworks from the beach before you eat. Or eat first and then head to the beach.
Even if you get the perfect ADR time, there is no guarantee you will be able to see fireworks from your table.
Do you know if they pipe the music on the beach?