Well, I would have spent my birthday at WDW this past september if it hadn't been for our ole' friend Frances! We had to push our trip back one week because of the hurricane. However, here's a few suggestions.
When you board your airplane...talk to one of the flight attendants and tell them that it's your daughter and husband's birthdays. You could ask if she could have the captain give them a HB wish when he does his little talk before the plane takes off or lands.
As for dinner shows, try the same thing. I don't know if they'll do it but find someone that works there and let them know what the situation is and see if they can anyway incorporate that into the show...even at the beginning or the end.
I've never tried it at a dinner show but a pilot did wish my figure skating team good luck at our competition once on a plane ride from Detroit to Alaska.
It doesn't hurt to ask...the worst that they can say is "no"...right? And you never know if you don't try!