Rey's new name

In the book Aftermath, which is after the Battle of Endor leading up to the Battle of Jokku, the Knights of Ren are introduced. They are already Sith affectionados and specifically are looking for Vader’s lightsaber. If I remember correctly, they found the Pyre on Endor, not Kylo, and took the remains of Vader’s armor. It was also addressed somewhere Disney, that Kylo’s cloak was the same cloak Luke threw away in the Rancor pit. There is also mention of Boba’s armor being in a sandcrawler, alluding to either the Sarlaac took a huge Boba dookie or Boba escaped and dropped his Beskar armor in the desert. That was also in Aftermath.