More detail about TFA from Abrams/Kasdan:
J.J. Abrams reveals that three actors lend their voices for that scene, that are quite familiar to us.
Ewan McGregor, Frank Oz… and a clever editing movie also brought the late Alec Guinness, who died in 2000 at the age of 86, back to the Star Wars universe. […]“You do hear a little bit of Yoda. You hear Luke yelling out, ‘Nooo!’ from that moment in Empire. And you hear Obi-Wan at the end say, ‘Rey … these are your first steps,’” Abrams says. “Here’s the cool part. We asked Ewan McGregor to come in and do the line. And he was awesome and we were very grateful. He was incredibly sweet and handsome, and all that stuff. Then he rode off on his motorcycle. Literally the coolest voice over actor ever.”
But who said “Rey”?
As they worked on editing the dream sequence, Bryan Burk, a longtime Bad Robot collaborator and one of the producers of the film, surprised Abrams one day with the gift of a single word: Obi-Wan Kenobi’s voice saying the name “Rey …”
“I said, ‘That’s cool, is that the thing from Ewan McGregor?’” Abrams recalled. “He said ‘No, we took a line from Alec Guinness saying ‘Afraid.’”
Frank Oz the famous puppeteer who also gave his iconic Yoda voice for The Force Awakens may appear in Episode 8, as well.
“He was incredibly generous and came in to Bad Robot, where we had a recording area, and he was doing Yoda, saying a number of lines we gave to him,”[…]That means, maybe, we could get even more of the character’s spirit in the films to come. Writer-director Rian Johnson (Brick, Looper) begins shooting Episode VIII next month.