Hi Shannon!
What a great plan you have and good job on securing a
most sought after Advanced Dining Reservation. Dining at 'Ohana is a must-do for our family, from the Hawaiian atmosphere, entertainment and plentiful (and delicious) offerings.
The last few times we visited during the dinner hour, we were not seated at our reservation time. I think your timing will be just fine. The 2nd floor of the Great Ceremonial House offers expansive and comfortable seating while you wait for your table and your meal will probably take about an hour and a half.
Cute shops at Disney's Polynesian sell themed merchandise you might want to check out before the fireworks, but I really don't think you'll need to bide much time. As you explore the Polynesian grounds lined with Tiki torches, you'll love feeling like you stepped into the Hawaiian Islands.
Don't miss checking out the nostalgic and magical
Electrical Water Pageant, too! Weather permitting, the floating parade will pass right by the Polynesian beach several times each evening.
I wish you a wonderful visit to Walt Disney World and please visit me again with any other questions coming to mind, Shannon.
Happy planning,
Sherri