If Rey’s a clone of anyone she should be either a clone of Palpatine or Vader, since they’re the lineages that Palpatine is known to value. Probably Palpatine himself, since Kylo is already a Vader child under his thrall.
I get this idea but I don’t think this fits the definition of a clone. A clone is genetically identical to the original. If it isn’t, then it isn’t a clone, it is something else.