Here's the deal with this situation. We can't know until next movie comes out. And while the music hint cannot be ignored, we do have to keep in mind that the statement that Snoke is a new character is probably true.
In the old movies, when George Lucas was writing the scripts for The Empire Strikes Back and A New Hope, he had didn't plan on Luke and Leia being brother and sister. But then, he decided while writing Star Wars 6 that they were going to be Siblings.
What I'm trying to say is that while they probably don't plan on Snoke being that Sith Lord, plans may change, just as they did in the old movies. So for right now, we can't know, but we might soon. Do you think plans are going to change?