Personally, I think that Supreme Leader Snoke could be Darth Vader's body, despite the fact that his body was indeed burned. The evidence?
1. His scar/gouge on Snoke's head. It is in the same place as Darth Vader's.
2. His body looks very burned and melted.
3. Kylo Ren is always saying to Darth Vader's mask to "show him the power of the dark side". Don't you find this to be just a little bit suspicious? After all, Darth Vader turned back to the light side... didn't he...? If Vader really turned back to the light side, why would Kylo Ren be able to feel Vader's evil in his helmet? However this could all be explained by the next bit of "evidence".
4. Now I know this is stretching it a little bit (okay maybe a lot), but I think that this could be Darth Plagueis using Darth Vader's body as a vessel for his soul. After all, wasn't Darth Plagueis so powerful with the force that he could create life from midichlorians, and even keep people from dying? Who's to say that Darth Plagueis didn't also keep himself from dying too? Perhaps (yes this is stretching it even further) He even created Anakin. Shmi did tell Qui Gon that Anakin had no father, and was conceived by the force, so maybe Anakin was created by Plagueis as a vessel for him, in case he died, after all, how could such a powerful sith not know how or when he would die?
This is just my opinion, you may or may not agree with me, but please don't respond with insults or name calling. You will be ignored. However, if someone wants to have a civilized conversation and/or debate about why you agree or disagree with me, or if you think I forgot something (which I probably did considering the fact that I only spent about 10 minutes on this post), please feel free to message me on facebook, comment your ideas, or even send me an email! (though I may not respond right away.)
Anyway, I hope you enjoyed reading my post! Thanks and may the force be with you all!