There's a post about it on the Transportation forum too. IMO they will be fine.
I've read that MCO airport has gotten a bit tweaky about toy guns, but since there's no such thing as a light saber in real life, they can't even get you about them being a replica. They aren't an actual weapon. We've taken up to 3 toy l'sabers in carryon and we've been fine.
We've even carried a Rebel Alliance blaster and a huge shiny silver plastic sword (from BBB's Knight's Package) in our carryon, got a sympathetic, funny, and sweet TSA agent, and got through fine. I would'nt do THAT again, but still, it turned out fine.