YES! We had dinner last year on our last night. I was with my dh and 2 children plus my parents. We had a seat in the window and at 8pm the fireworks went off. My daughter said something like "I'll never forget this night" and my Mom started bawling! It was a special WDW moment.
We made reservations for this trip (2 weeks!) at 7:10. Fireworks are scheduled that night. I plan to call Ohana the minute they open that evening, mention my ps, and ask to have a seat by the window again. Even if there are no fireworks when you go, the view of the lit castle is wonderful.
Have fun! Ohana is a wonderful, fun family place.