[@WhiteStar19] or we could have them grow up as normal kids in the normal world and a curse has blocked their magic from being expressed. Then with a little Once Upon A Time drama and whatnot they find out their magics have been taken and they need to gain them back for safety reasons. (maybe there's a OUAT alike problem approaching them.) 
With that we wouldn't have mind loss, no backstory problems and a total new world to open up
I would also add that those without powers (Rapunzel, Anna, Cinderella, ect) get to choose one power that fits their characters. If they want to.