Just to run with the Plagueis theory, why Han/Leia know Snoke, why Kylo seems to be protecting Rey, and why Rey was left on Jakku, and why that Pablo dude has said Rey was never at Luke's academy.....
Plagueis created Anakin Skywalker. In order to bring down Sidious, who had attempted to kill him. When Vader did so, balance was restored. Now Plagueis can return from the shadows. But with Anakin's offspring now older and strong in the force, Plagueis attempted to seize control of them, of Luke especially, and thwart him from creating more Jedi. When Kylo was old enough, Plagueis saw in him that same Vader potential. Needed him to bring down Luke, to fulfill the prophecy again, the circle repeats, thru the Knights of Ren. Plagueis has the whole Skywalker family under his grip. Why Han/Leia know about Snoke (if he's Plagueis). He's tortured the Skywalker family for decades. Used them for their power for his own gains. The family Skywalker wants out of this wretched circle. Luke, Leia, Han, Kylo, they all want to protect Rey from Plagueis. Keep her hidden from him. So an elaborate complicated complex mess is in place. Where Kylo is really heading for redemption, really out to fulfill the prophecy again, to kill of Plagueis but has to do it thru so much sacrifice himself....conferting to the dark side, killing so many, killing his own father tho he can't bring himself to do it, all to get closer to Snoke and finish his training, learning everything there is to be learned, finding his weaknesses so he can be finally and utterly destroyed to free the Skywalker family from his grip. But Rey getting older now, and Snoke out to destroy Luke, it's sped things along. Rey is in danger now, with Snoke having cottoned on to her, and her using the dark side to defeat Kylo.