It’s an interesting theory, but I don’t think Rey necessary needs special parents. I don’t see a contradiction between Rey being an important figure and her parents being nobodies.
Look at Anakin. His mother was a slave and presumably he didn’t have a father. But he was not just important, he was the prophesied Chosen One, the one who was supposed to bring balance to the Force.
I think Rey is the next Chosen One. That’s the connection she has to the Skywalker line. That’s why she’s so strong in the Force. That’s why Luke’s lightsaber called out to her.
The evidence for this is in a line of dialogue from Snoke:
“Darkness rises and light to meet it. I warned my young apprentice that, as he grew stronger, his equal in the light would rise. Skywalker, I assumed. Wrongly.”
I don’t think this was just idle banter. With everything Luke said about the balance earlier in the film, I take it to mean that the Force itself imbued Rey with great strength and sent her out on a quest to restore balance.
Of course, this theory could be true, and it still doesn’t mean she’s not a clone.
“Since the Emperor is only now revealing himself, it’s reasonable to think it took Imperial scientists a while to figure out this process — otherwise Palpatine would have been back in charge of the First Order years ago.”
I will point out that just because we haven’t seen Palpatine so far, does not mean that he hasn’t been pulling the strings and running the First Order from the beginning.
That said, the first idea that popped into my head when I heard Palpatine’s laugh is that he’s not alive at all. That Rey and our other heroes have to go to the Death Star ruins to retrieve some macguffin, and they find that it is haunted by the malevolent spirit of Palpatine. We know that Sith and dark side Force users can’t become Force ghosts in the sense that we’ve seen them before — they can’t pop around the galaxy at well — but that’s not quite the same thing as dark side energy haunting a specific place. Like the cave on Dagobah.
But I could be wrong about that. I believing my thinking on Rey’s origins is well evidenced, but my speculation on Palpatine is just that, baseless speculation.
I will say that there’s one kernel of possibility I’ve thought of which might support your theory.
Luke’s lightsaber. We still don’t know how Maz got hold of it. Whoever found the lightsaber — Vader, perhaps — presumably would have also found Luke’s dismembered hand. Which could have been used to harvest his DNA.
“The strangest rumor about Episode IX is that Revenge of the Sith’s Hayden Christiansen is going to be starring in it. It sounds bonkers, but what if he’s playing a clone of himself? Who would he play other than a clone of himself?”
Well, my assumption is that he would be playing Anakin’s Force ghost.
Remember, Lucas photoshopped Hayden Christensen into Return of the Jedi as a Force ghost.
But “clone” is another possibility.