The seven lights are Micky, Sora, Riku, Kairi, Aqua, Ven, Lea.
Mickey says that the 7 are Mickey, Sora, Riku, TVA, and one unknown. Xehanort says that there are three missing because Sora is about to become a vessel, Terra is already a vessel, and there is one unknown. Since Sora is saved, the the seven lights are Micky, Sora, Riku, Kairi, Aqua, Ven, Lea.