Saw a post propose that Rey is Sabé’s (Keira Knightley’s character) daughter, sent to train with Luke.

This is close to my headcanon, so wanted to put this out. It’s based upon how perfectly it aligns with the SWU business plan for their transmedia (comics, TV series, side films, books, and saga films) and what an enormous and unprecedented opportunity Disney would have to take advantage of the absolute gold of a situation in which an actor in a tiny role goes on to be a movie star. 

My headcanon is: Sabé is her grandmother, Obi-Wan her grandfather, 

There are canon comics now covering what Obi-Wan was doing between Luke’s birth and their eventual meeting on Tatooine. The concept is that Obi-Wan left behind journals in his home with a note that says “For Luke.” Luke goes to Obi-Wan’s home shortly after RotJ and finds and reads them. They are being released as “The Journals of Ben Kenobi,” and the first was out last summer, the second is releasing next month. Seven are planned. 

This means SWU canon wants us to consider what Obi-Wan was up to all those years. 

Ewan McGregor is on board for an Obi-Wan standalone film. Keira Knightley is a movie star now, and Daisy looks like her, but not Natalie Portman. Their age diff is exactly the same as the Harrison/Carrie diff. Keira also has a relationship with Disney (Pirates of the Caribbean), and nobody would turn down Star Wars, so she is a sure get.

The best possible business decision would be to get Keira and Ewan on board and let the Obi-Wan film explain their relationship. The thing is, in the non-canon EU, Obi-Wan does fall in love at one point in his life. He just has duties and can’t stay with her. It is very easy to see that - like with Rey - anything that took him off the desert planet where he was waiting for Luke to come to him would have to end, because he would return to Tatooine as soon as possible. There is something really poetic about “You’ve been so lonely, so afraid to leave” applying equally to Rey and her grandfather, as each spent all those years waiting for Luke to show up.

So, my headcanon is that Sabé sought him out for help, they had an adventure and fell in love, but he had to return to wait for Luke to come to him - as he knew he would since canon holds that he left a trunk full of journals for him before they left Tatooine, obvs - and she had to live whatever life she had to live…

…and the reason he left the journals for Luke is that he knew Sabé had a child, that he had a family, and he wanted Luke to see to their well-being. Rey would’ve been born a bit over a decade after RotJ, so the timing is good. If he found them, when they had Rey, he would certainly take her to train.

It should be noted that this also means that if Sabé and Obi-Wan had a daughter she would be the perfect age for Luke, so this doesn’t preclude Rey Skywalker. This is just my thought on the best way Disney could use the SW intellectual property the Marvel way, which is what they clearly want to do.