Fireworks will be at 10pm this Saturday. When we're at 'Ohana, we usually take around two hours normally for dinner (two adults), but I hear that others usually only take an hour. If you're finished with dinner, don't wait around at the table, because they need to turn it - just go down to the beach where the view is much better, anyway.
I believe the water pageant is at 9pm? Not sure on the exact time.