No need to worry about percentages, this news is 100% true: Nintendo's just revealed Lucina and Robin from Fire Emblem: Awakening are in the Super Smash Bros. roster, along with the familiar returning face of good ol' Captain Falcon.
If you're wondering who Robin is, that's the default name for your playable avatar in Fire Emblem: Awakening. As per the 3DS tactics RPG, you can play as either the male or female Robin in Super Smash Bros.
Super Smash Bros. (Lucina screens)
Super Smash Bros. (Robin screens)
Super Smash Bros. (Captain Falcon screens)