Probably none of them 
Florida - would want to save it for when she's older and will appreciate Disneyland
Cruise - would depend on how much time off the ship, I can do activities at home, I like to go exploring. (oh, and I get seasick
I know you're not supposed to on cruise ships, but I'd want to be sure of that!)
Dubai - I don't much about it, but my first impression is that it's just luxury hotels and shopping. I couldn't be bothered to sit on a plane that long, just for the weather. I'd rather go somewhere I could do more sightseeing.
I think in your shoes, it'd be the cruise though - it sounds the most fun for Z.