To prove she is a Skywalker (which she is), we first have to disprove other notions about her origins.
Please do not read if you haven't watched The Force Awakens, lots of spoilers follow!
Lets start with the Kenobi theory.
If you have ever seen episodes I-III, and we all have, you know how Kenobi felt about the Jedi Code. He was one who believed in the way of the Jedi, and there is no way he would totally abandon one of its' core principles.
The argument has been made that Kenobi may have been disheartened after the fall of the Jedi and stopped following the code. Lets take a look at a period of time where he could have turned his back on the code, and worked with someone he truly loved more than a brother. (You really only need to watch until the 1:42 mark, but I wont hold a grudge if you want to watch in its' entirety.)
Whew. Say what you will about the sequels, this is easily one of my favorite movie scenes of all time. Beautiful.
Back to my point, Obi-Wan could have turned his back on the Jedi Code, worked with Anakin and together defeated the Emperor. No one could have stopped him and there would have been no real repercussions. The Order was gone and there was no one who could punish him for this decision. But he stays with the Code. He states that his allegiance is to Freedom, to Democracy! These are staples with the Jedi. Core values as it were.
Based on this, and other examples of his resolve, we cannot just assume that he would suddenly give up everything he has been taught since basically birth.
Either way, if for some off-the-wall reason he were to abandon the code, even for one night, and a child was conceived from it, this child would be too old. Even if the child was born the last night he was alive on Tatooine, he/she would be 34/35 at the time The Force Awakens takes place. This defeats that argument.
However, one could easily say that this child may have had a child and that is Rey. I feel as though we are going out on a limb at this point. I find it extremely hard to put that in Star Wars. The next scene would be Luke staring at her and saying, "You know that guy who trained me? He turned his back once on the Code and had relations with someone on Tatooine and felt bad about it. A child was born who lived in secret from Old Ben, and later that child had a child and that was you!" I don't think that Abrams would do that to the audience. Obi-Wan would've known about this child and not made the comment that Luke was the last hope for the galaxy.
Either way, if, again, by some off-the-wall reason this is what happened, why would they leave their child on Jakku? It just makes no sense when you put the pieces together.
Now the idea that Rey is a 'Solo'.
For this to be true, Han and Leia would've had to given birth to another child. This is obviously feasible, and could potentially fit the timeline. But, Han's reaction when he hears that she is from Jakku makes no alarm bells go off. Everytime he saw Kylo Ren in The Force Awakens, he had a moment of close-up with the camera. He had such a deep pain about the loss of his son, we can extrapolate that he would've acted the same way with his long lost daughter.
Another hole is, why would they leave her on a desert island? Neither of the two have any ties to deserts, save for the fact that Han just so happened to be in Mos Eisley and that Leia's brother was raised on a desert planet. Leia also makes the comment about letting Ben go and train with Luke and that 'That was when I lost him.' If Rey really was their long lost daughter, Han would've told her in that moment and all would be right with the world. There is also the fact that Kylo seemed to have no knowledge of her as a sibling. I believe it is safe to assume that when Rey was left on Jakku, it was around the same time the fall of the New Jedi Order happened (More on this soon). Kylo would've known he had a sister and probably would not have withheld this information when interrogating her.
The theory just doesn't add up.
Now, for the main event. Why Rey is a Skywalker (a.k.a. Luke's daughter).
The amount of similarities between the two are way too coincidental. I have made a short list of them:
- Both hail from a desert planet with no real 'parents' to speak of.
- Both find a droid carrying secret plans that could potentially lead to the defeat of an evil organization.
- Both leave said desert planet in the Millennium Falcon.
- Both are given a lightsaber that belonged to a powerful Jedi. (Based on my theory, both were given their fathers lightsaber.)
- Both have innate aptitudes with technology. (Her and Anakin were one of very few shown to be able to understand BB-8 and R2-D2 respectively without any assistance.)
- Both are phenomenal pilots. (Rey flew the Millennium Falcon by herself with very little difficulty.)
For the sake of brevity I have ended the similarities here, although there are still many.
The Downfall of the New Order happened around the time Rey was left on Jakku, as far as we can tell. I believe the argument can be made the he left her on Jakku to hide her from Kylo Ren. He just finished killing the other Jedi and he clearly would have gone after the daughter of Skywalker. Luke knew she would one day be a major player based on her lineage. He hid her on a planet that is eerily like the one he was raised on. This fits well with what we know of the story so far.
One can also argue that Luke abandoned her on Jakku because he knew what might happen if she formed emotional attachment to her parents. Vader was an all too clear example of why this should be avoided.
We must also not look over the fact that the lightsaber CHOSE her. Why would a lightsaber that belonged to Anakin and went to Luke choose her if she wasn't Luke's daughter. The Solo origin could potentially hold water here, but it's still pretty thin. The lightsaber chose her because she was the rightful heir as Luke's daughter.
There is also a fairly large coincidence that seems extremely unlikely in the beginning of the movie. Lor San Tekka, (the old man who gave the piece of the map to Po) was on the same planet as our new Jedi protagonist. Logic stands that Luke may have asked him to keep an eye on Rey and gave him the final piece of the puzzle to give to Rey when she was ready. The only problem is, the First Order grew too strong and Lor San Tekka believed they needed Luke's help. Thus, he reached out to the Resistance in hopes of helping them find Luke.
Here is the most crucial and overlooked piece of information that makes my theories work. When Kylo Ren first looks into Rey's mind he makes a very clear statement. He says, "I can see nights of loneliness, isolation. You dream of an ocean. I see the island." Fast forward to where we find Luke. Drumroll please....
AN ISLAND IN THE MIDDLE OF AN OCEAN.
I believe she was either born there or Luke brought her there before dropping her off at Jakku. She longed for that place, the last place she was with her family. IT ALL FITS.
So there you have it folks. I have a few more arguments but these are the strongest I have came up with. I hope you enjoyed reading and please leave a comment with your ideas!