Welcome aboard Erica. I've got to go along with M767 on this one, nonrevving Hawaii in July with your family is a recipe for stress and sleepless nights.

My sugggestion for your family beach vacation is San Diego. There's the San Diego Zoo, Sea World- (with Shamu ), Legoland, and some nice beaches too, plus you get to fly on your own metal.
Good luck and do let us know what you decide.