The [canon] SW novel Bloodline confirms Rey's vision of Kylo and the KOR couldn't have been a flashback because Kylo turned to the Dark Side less than 6 years before TFA. Rey would have been 14/15 when it happened, not the five-year-old girl we see being dropped off on Jakku.
The scene is designed to confuse people and make them think that's the past and the KOR have just slaughtered Luke's Jedi Academy. But that's not the case at all. That vision is happening in TLJ. They're on Achto.
I know people think this...but its just not true.... it is a scene depicting the fall of Luke's school and the people supporting it.
Its in Chronological order, as it is in the book.
1. Rey sees Luke fighting Vader on Bespin.
2. Luke Giving R2 his map piece.
3. Rey being left on Jakku
4. Kylo killing the last people in the way of Finding Luke, and his school (or perhaps something else).
5. Rey in the snow meeting Kylo for battle
No one said Rey was dropped off on Jakku
AFTER Kylo turns to the dark side...that's just the internet assumption. Luke often saw the future...perhaps he knew what would be coming with Kylo, and hid Rey early knowing what could happen. Hell anyone could have dumped Rey.....Even a jealous Kylo
We also do not know WHEN Kylo actually became noticed by Luke as a potential threat.
I have always surmised that Ben was troubled early on when Han and Leia were having relationship problems. I think they couldn't handle his force abilities and perhaps he was disturbed from the start....they turned to Uncle Luke to help put him on the right path.....but as Han and Leia failed at controlling Kylo....so did Luke.
Knowing that Kylo was being led more and more by Snoke. Luke sends Rey away knowing she would be a bigger threat if tainted by Snoke.
Kylo continues to descend into his madness/obsession with Grandpa Vader and becoming the most powerful force user in the galaxy... Egged on by the mysterious Snoke and meeting another similar minded group (Knight of Ren) and begins his quest to become as powerful as possible by any means needed. Snoke convinces him that killing his (kylo's) perceived root of all problems ...His Father (He would have disappointed you)will free him from all the pain he is feeling but cannot understand. By this logic...I am sure Snoke will also try to convince him to kill his mother also.
The question is what is in all this for Snoke.
I think Disney will use this film as a platform to make a statement about mental illness and perhaps absentee parents. Kylo was a misunderstood kid...probably left alone for long periods of time while Han had midlife crisis and Leia was too busy managing a fledgling government. Kylo left alone...meets up with the wrong crowd, and is convinced they only way to feel safe/in control, is to be able to destroy anyone or anything that poses a threat to a world that frightens him. Total complete control over the universe is the only way.
This is very close to the psychologial profile of the school shooter....which is exactly what I first though of after seeing TFA. He clearly show signs of Sociopathic Dissociative Disorder. People like this often suffer from emotional outbursts and wild mood swings.
Like many School Shooters Kylo has;
Distorted thoughts.
Cries for help
Seeking Respect
Fantasy Thoughts and Idolization of other powerful people
Violent youthful experience
I hope they do shine some light into this realm with him. It would make for a great character..