I’ve been trying to develop a headcanon to make this movie’s Snoke stuff less ridiculous in the wider continuity. Here’s where I’m at.
First of all, Palpatine’s line, “I made Snoke,” gives the immediate impression that Snoke came fully-formed out of a tank, because the next thing we see is the tank with another Snoke in it. The line itself doesn’t have to be that literal, though; it could just as easily mean “I made Snoke what he was,” i.e. he corrupted an existing individual. My preferred version of events is that Snoke was a dark side adept who went exploring in the Unknown Regions, stumbled across Exogol, and was bent to Palpatine’s will. I don’t hold out much hope for this to be canonized, but it remains plausible at this point.
If Palpatine did literally engineer Snoke, though, I’d prefer if it wasn’t for the explicit purpose of fronting the First Order after the OT, because that either means that Snoke was doing nothing for decades, or that he’s actually roughly the same age as Ben Solo. I prefer to think that Palpatine employed Snoke as an administrator for the Sith Eternal cult in the Unknown Regions, and that Snoke in some capacity oversaw the creation of the Sith fleet. I like this version of events because it leaves the door open for some PT-era Snoke stuff in Zahn’s upcoming trilogy about Thrawn in the Unknown Regions.
What about the new Snokes in the vats in the opening of TROS, though? I think that if Kylo Ren hadn’t found Exogol, Palpatine would have sent another Snoke out into the galaxy to sow doubt about whether he’d truly been killed. Palpatine’s strategy has never been based around a single master plan; he prefers to set up a series of contingencies and failsafes so that he comes out ahead no matter what happens. Those Snokes are on ice just in case they become useful later. That’s why they have the injuries that we know Snoke received relatively recently as of the time of the ST; it’s not to suggest that the original Snoke was designed to look all melted and fucked up, it’s because the new Snokes are meant to replace Snoke prime and need to match him.
I don’t know, it’s all pretty dumb no matter how you look at it, but I’ll feel a lot better if they canonize some degree of agency/significance/history for Snoke. Apart from the few bars of Palpatine’s theme that play when Snoke is interrogating Rey in TLJ, there isn’t a whiff of the “man behind the curtain” trope throughout the rest of the ST, and it feels really sloppy and flippant to say in the third film that the big bad in the first two was a literal puppet and not go into any further detail.