Here are a few details that are my favorites going along the line of what Rachel says she likes and some ideas that I like. I decided to put them in one place. In some cases I'll put my top two choices.
Rachel:
This dress:
With a navy sash and broach, except with sash longer and tied different.
Green and white bouquet or yellow bouquet.

Bridesmaids:
Green and white or yellow bouquets.


Other Decorations:
If this were possible. It would be cool! Maybe just string clear lights across the ceiling.
Guest book table: Bird cage for cards with lanterns and framed bridal photos.
Tables:
Blue tablecloths, runner or square in middle
Main centerpiece of willow branches and yellow tulips with a few small vases of green hydrangeas.

Or
A combination of these two bouquets. Yellow tulips, white tulips or roses, and green hydrangeas.


Seashells and coral surrounding the vases. Why not? Poly pride. ;)
Wedding Cake:
Either a 3 tiered round or square cake with navy ribbon and yellow and green flowers.
Food:
I wouldn't do food since there will be a separate luau.
Assorted candies and mini takeout containers for people to fill. Cute?
OR
Dessert buffet. Yummy!
You could always do cupcakes or sheet cake.