In our area, the rehearsal dinner is always a more casual, laid back place where you can have a good time with your friends. Because of that, I wouldn't do a signature spot (Jiko, CA Grill, Artists Point, Yachtsman, etc).
'Ohana would be a lot of fun with a group. It's served family style so you don't have to worry about individual orders. They have a bar that you can order great Poly inspired drinks. There is some entertainment and a loud, lively atmosphere. If things get awkward around the table, it's not noticed because people are watching the kids doing the hula contest and such. They can also easily accomodate a large table. If you hit it just right, your party can view Wishes from the restaurant. If you eat a little earlier, your party can go to the Poly beach and watch it.
OUR bridal party would have loved an evening at Raglan Road. In the evenings, they have an Irish band and Irish dancers perform up on the bar - it's very adult centered late in the evening and very drinking centered =) Great food, fun fun fun atmosphere, fantastic drinks. You can get there for dinner at 730 or 8, people who want to retire early can, and your friends can stay for the party after dinner.