Fans have a lot of questions about Supreme Leader Snoke going into Star Wars: The Last Jedi and that has led to numerous fan theories about who the character really is. A whole host of related theories have now been debunked by somebody who would know. Dave Filoni is the executive producer of the animated series Star Wars: Rebels, and he's seen a lot of fan theories that connect Snoke to the characters from the series, specifically Jedi in training Ezra. Filoni is clear that there's no connection between Snoke and Rebels, though he admits that he understands how such theories could get started. According to Filoni...
I try and beat around the bush. I like reading the fan theories, and when I read them, I think, 'Well, there's no possible reason that that can't be true, it's just not true.'
As it currently stands, there just isn't a lot of information about Supreme Leader Snoke, and that lack of information ultimately means that lots of different ideas can be used to fill in the gaps. As Dave Filoni tells ComicBook.com, that means that many of these fan theories could be true, he just happens to know that they are not.
Star Wars Rebels follows a Jedi Padawan named Ezra during the years prior to the original film trilogy. However, since the character seems to have completely vanished during those films, as well as Star Wars: The Force Awakens, it has led some to surmise that Ezra went down a dark path following Rebels and became Snoke. It seems that this will not turn out to be the case. Though, even the executive producer admits that he understands that there's nothing that currently proves that the theory is untrue.
The identity of Supreme Leader Snoke has generated as many fan theories as the origin of Rey at this point. He's clearly a character of power and authority, so much so that it seems odd that he would not have shown his face previously in the Star Wars universe. This has led most fan theories to suggest that we have seen Snoke before, just in some other form. Everybody from a still alive Emperor Palpatine to Grand Moff Tarkin has been suggested as Snoke's true identity, and while these theories, like the Ezra theory, could be technically possible, as we have no evidence that they are not, most of them, if not all of them, absolutely are not true.
The most recent trailer for Star Wars: The Last Jedi shows us that we'll finally see Supreme Leader Snoke in the flesh, which would indicate we'll be learning more about him, whether we'll get enough to confirm any theories remains to be seen.