ok.....those theories are getting worse each time
When trying to predict what will happen next in a piece of fiction there are a limited number of tools. There's the work itself and whether the author used foreshadowing or included clues. Then there's what the artist has said in regard to the work. Then his basic philosophical views, outlook on life, and general personality ...and finally, their collection of work or influences.
There's a bunch of stuff in TFA that is either extremely lazy writing (Mary Sue complex) with Rey being almost on the level of a Jedi Knight, being able to fly almost everything she touches, and speak almost every language despite being isolated in a desert.
This leaves two possibilities:
1. They wrote themselves into a corner as we nowhere in Star Wars lore has it ever been shown that a normal force-sensitive can "train" themselves. Ever. They basically fucked the pooch.
2. Rey is special as fuck. As in Anakin-level special, as he's the only character in Star Wars history that was able to display his powers without training. Whether she's Anakin? I don't know. But she's Luke's daughter, a random girl, or anything like that. She's more force sensitive than even Luke was.
The second is what I'm going to go with because if it's number 1, then the franchise is fucked.
So why is Rey special? We have to look at what Abrams (and others working on the project) have said, what else they've written, and make educated guesses. Boys in Brazil is an obvious influence on him, as if you've watched the movie, you notice fucking parallels between it and TFA. It WAS an influence for Episode VII.
So here's what we know. The Empire had a super secret base on Jakku that it defended at all costs and they were experimenting. Cloning in the Star Wars universe can be done, but a force user has never been cloned. They could have been knocking on a very particular door, cloning a force user. Who is the most powerful force user who's DNA they would have access to? Vader/Luke. That saber that was found? It had a hand that went along with it.
Girl shows up, Mary Sue's her way to victory. Very mysterious backstory and origin. If she was a random force user, it'd have been explained in the first scene. If she's Luke's daughter, they wouldn't go through this much secrecy about it.
...no, when you add it up Rey is most likely some incarnation, representation, or at least on the same level as Anakin Skywalker with a very interesting origin story (probably cloned).