SPECULATION What is Rey last name ?

I don't think she has a true last name --- if she doesn't it would be a big clue to her real ancestry. Being the protagonist of the trilogy and one of the few main characters without a last name given to us seems odd to me. The Force Awakens teased the question of who her parents were but I think the way it was presented (parents leaving on a ship with her alone on Jakku) may be a red herring.

Also, didn't Daisy say that she thought the question of who Reys' parents are was settled after TFA? Yet the movie doesn't seem to indicate any obvious clues as which characters or lineage that might be. Maybe it's because we shouldn't be looking at characters or lineage. "Parent" has a pretty broad definition. Also, when I think of the title "The Force Awakens" I think of a rebirth of the force.

In TLJ when Rey goes into the hole on Ach-to to discover who her parents are, instead of seeing other people, she sees versions of herself. When Kylo said she's a "nobody", that was probably to deflect her from the truth; he doesn't want her to fully remember who she really is, and the enormous power she has, because she might really be far from a "nobody"!

 

Being saved for Episode 9.

 

It's Minch

 

New here but it Rey Gunn because that is awesome!

 

Well, what do we know about Rey? First, she’s a scavenger. She ranges all over looking for scrap. So she’s a rover.
Second, she’s pretty handy with fixing mechanical apparatuses and sorting out how they work. So she’s a machinist.
Lastly, she has no real identity of her own. She’s a complete nobody from absolutely nowhere. So she’s a no one.

OK, put that altogether: a rover, a machinist, a no one and what do you get? RO + MA + NO.

There, perfect. The absolute best possible name that both reflects her as a person and commands unwavering respect from all who hear it.

“Rey Romano”. I did it. I stitched this elaborate puzzle together. I now dare anyone to find even the smallest flaw in my impeccable logic. Good luck.

 

You've almost got it. You forgot the most important piece. In TLJ, at the end, she cuts Ben off from her Force Connection. Luke too, at the beginning of the film was cut off from the Force. As you can see, the theme is being cut off. Limbs cut off, information flow cut off, the Force cut off. Cut. OFF.
Put it all together and you've got "Rey Romanoff." You see, the entire Star Wars Sequel Trilogy has been a crossover with the MCU from the VERY BEGINNING.

 

If Rey was intended to be not related to any character in the previous movies, they should have kept it to Kira Rey. No one would question her identity. But no, Abrams had to make Rey to keep the mystery box alive so that people can keep watching the movie and guessing only for there to be no answers.

 

http://www.fantasynamegenerators.com/fantasy-surnames.php#.WqRFF-dG1PY