Yeah, pretty sure the clone-son thing was a retcon from someone at Lucasfilm who couldn’t stand the ick factor of Palps having biological offspring.
I always understood the lore around Palps “son” to be that the bodies only deteriorated once his spirit went into them, since the bodies couldn’t contain that much force. With the son though, since he had no force connection Palps couldn’t enter him, so his body didn’t deteriorate
I guess this is the closest to canon yet. I always got the feeling that the reason Palp’s body was so deteriorated was because clone bodies cannot hold the Force potential of their host. This used to happen in Legends with the clones of Jorus C’Baoth and Luke becoming mad.
Sidious being a literal clone can be reasonably deduced from the movie and Hal’s edit reinforces that idea with the Palps bodies grown in vats. But there’s no indication that Rey’s father himself is a clone without looking into expanded material.