I just realized that the Force Awakens essentially “retconned” (does that mean written out of canon?) the PT. The PT made clear that Vader was destined to destroy the Sith based on some ancient prophecy, and I’m assuming that Kylo Ren and that fish guy in the hologram are Sith - or at least the equivalent. So basically all that nonsense about the space prophecy and Vader being the savior of the universe was irrelevant.
The Nightsisters in TCW aren’t Sith and neither is Kylo Ren and his master. Abrams mentioned that Kylo Ren isn’t a Sith. Therefore, the prophecy is irrelevant to TFA. It never said “destroy the dark side.”
If Snoke is Plagueis that would obviously trump Abrams’ statement and of course Kylo would emerge a fully trained Sith Lord when he completes his training.