Why Supreme Leader Snoke is Really Jason Todd
I mean, it's about as probable as any of the other Snoke theories out there. Snoke is Vader. Snoke is Palpatine. Snoke is Plagueis. Snoke is Jar Jar. Snoke is Tupac. I think what people are not taking into account, is that even though the EU (rebooted in 2014) and both CGI Star Wars series are canon, sharing a cohesive, singular universe, the love does not go both ways.
Sure, Leia, Lando, Vader, Yoda and the Droids all make appearances in Rebels, with those encounters being canon events in the Star Wars saga. But they do so as a matter of course. To establish the validity of the series as canon. To make clear to the viewer that this is, indeed, part of the larger Star Wars universe. But something like Leia's cameo is like an actual princess descending on the common people and gracing them with her presence. If you're the EU, don't expect to be invited to the royal palace on Alderaan for dinner anytime soon. The films are Star Wars royalty. The EU are the second-class citizens.
And that's even acknowledging that quite a few concepts, locations and characters found their way into the the films and TV series. Aayla Secura (Star Wars #19), holocrons (Dark Empire #5), Coruscant (Heir to the Empire), the Outrider and the Black Sun crime syndicate (Shadows of the Empire) all made the crossover to coveted G-canon and T-canon status, avoiding being relegated to reference work by Lucasfilm's 2014 reset. But for the most part, these were consolation prizes. A city, a background character or an artifact could easily be fit into whatever plans filmmakers already had. (Aayla Secura, for example, was added to Episode II during post-production on a whim.) But major plot points, significant characters, pivotal moments or reveals never made it from the EU to the big screen. Even cartoons, which might be considered the Dukes and Duchesses of this proverbial royal family, only get a seat at the royal table by special invitation or circumstance.
Two notable examples would be Boba Fett and General Grievous, who both made their first appearances in cartoons. However, in both cases, these characters were borrowed from existing film projects that either hadn't been released or were in the middle of production. In Fett's case, he was already an existing film character, but his debut scene in A New Hope had been cut. He ended up making his first public appearance on The Star Wars Holiday Special in a cartoon segment. And in Grievous' case, he was introduced in the Genndy Tartakovsky Clone Wars series which was pretty much just a great big promo for Episode III.
Major characters from the cartoons, comics or novels have yet to make a significant impact on the actual Films. And, interestingly enough, the cartoons have traditionally had less of an impact on the Films than the print media has, even though their canonicity is second in importance only to the movies. I said earlier that movie characters and concepts make their cameos in the cartoons and print media because it's necessary to reinforce to their audience that this is all taking place in the Star Wars universe. The movies, however, don't need this reinforcement. They movies ARE the Star Wars Universe. They decide what happens everywhere else. Even in those rare instances where something occurs in the EU first, it was because of a collaborative effort to introduce to you to, or promote, something initially created for the movies. There's not a lot of time in between its introduction and film appearance, say, two entire years, such as when we'll see Snoke again, otherwise it'd defeat the purpose of the promotion.
In light of this, it's highly unlikely Snoke is anyone from any of the CGI cartoons, comics or novels or that the filmmakers and the Rebels showrunners collaborated on a two way street. Yeah, there's a crossguard lightsaber in Season 2. But where did we see the concept first? Sure, the Inquisitor bears a striking resemblance to Snoke. But so do half a dozen Sith Lords and Dark Side users in both canon and Legends history. (Dark Side Effects may include alopecia, skin irritation, eye discoloration and loss of pigmentation. If you don't feel the need to kill a family member or loved one for 24 hours, consult your Master immediately. Scarring, disfigurement, dismemberment and some form of mobile life support are normal. Don't use the Dark Side if you don't forever want it to dominate your destiny or if you're lactose intolerant.) Connecting the old with the new might feel like the natural thing to do, especially with Star Wars. But other than a few superficial physical appearances, there's literally 0 evidence to suggest he's anyone from Star Wars' past. That doesn't mean he isn't beyond all doubt. But saying that he is is a guess based on nothing more than an appearance a lot of Star Wars characters have, just by nature of who they are.
One of the other, more popular theories thrown around is that Snoke is actually Darth Plagueis, Palpatine's Sith Master, whose murder he not-so-subtly recounts to Anakin at an opera in Episode III. While the original Darth Plagueis novel was relegated to Legends status, there were a couple of details that likely still hold true. One, being that Plagueis was Palatine's master. And two, Lucas instructed James Luceno, the author of the book, that he wanted him to be a Muun.
If you don't know what the Muun are, you probably just didn't know them by name. And this is part of the problem. The Muun look like this...
In fact, that's one of the artists interpretations of Plagueis there on the bottom right. Muun are long, and thin and bear no resemblance to Snoke physically (other than the aforementioned baldness), even if you factor in his disfigurement. Surprisingly, folks are cherry picking the details from interviews with Andy Serkis, where he describes Snoke as tall and having "a very distinctive and idiosyncratic bone structure." Another interviewer described him as thin. While this could describe a Muun, Snoke clearly doesn't look like a Muun. Conversely, when Serkis is asked about Plagueis, he specifically says he's not. Which, you'd think, would be enough to convince fans, considering their taking his other words as gospel. Then again, his other words in no way confirm that Snoke is Plagueis, especially in the fact of, well, the face. The bone structure is just too different.
I also find it unlikely that they'd retcon this EU aspect of Star Wars canon. Mainly because this is only EU by virtue of the fact that it only exists in George Lucas' notes. Previously, Lucas' notes were gospel, whether those details had made it on-screen or not. If the movies are royalty, Lucas was their Supreme Creator. And those details, as far as I can find, have yet to be altered in any way. Details like Chewie's age, his life-debt to Han, the species designations and home planets of background aliens, have all managed to survive into existing official lore. This would be in keeping with the old days, a decade before the Prequels, where hardcore Star Wars fans already knew about the volcanic final battle Obi-Wan gives Anakin his molten rock makeover, the Wookiee homeworld Kashyyyk, and how a Senator named Palpatine would seize power of the Old Republic and become Emperor of a new Galactic Empire. We'll only have two opportunities to make an educated guess about how Lucasfilm without Lucas will do a Star Wars movie. By speculating on 8, based on what we saw in 7. And by speculating on 9 based what we see in 8. Once we get to 9, there will be nothing else to speculate on. So we're 50% of the way there when using that standard. Based on what we know, there's no real reason to think they'll ditch the idea of Plagueis being a Muun. And Snoke clearly doesn't look anything like one.
I love fan theories as much as the next geek, but this is one of those theories gaining steam from wishful thinking alone.