My analysis, because I'm definitely getting killed tonight:
Can't be Autolycus, as he also tried to put Newyn in the lead that day after day had been extended.
Couldn't be Visorslash, as was also apart of the Newyn flips back and forth though finished by not taking a stance and voting Takhisis at the end. However, when the day was originally supposed to end, had his vote on Newyn.
Could be Snerk, but Visor, I have to know what the Sable mask does/did to know for sure. Specifically if the mask enabled KM to be a vengeful lynchee or if it did anything other than that. Voted Spaceman at the last second on the original day two end time to tie vote with Newyn, so that's a black mark. Newyn's vote here on Snerk is interesting - he's either bussing (doubtful, he'd be the solo guy left after he got roleblocked the previous night) or he's trying to buy another lynch with his fake seer claims.
Split on Legato, slight lean to scum. I don't have a whole lot to go on here. On one hand during day four, he had an opportunity to vote either me or Visor to put one of us in the lead (we were tied at 2 each), but instead voted Autolycus to tie him with us. If he's scum, I'd expect him to try and distance someone from the pack (even something as subtle as a 3-2 vote margin) as opposed to voting another townie into second place. That said, I could see a scum player doing just that by putting another townie in the crosshairs, since no other scum player was under threat. If he's scum, I'd also expect to see at least a handful of mask votes to Newyn. In fact, we see hardly any mask votes at all. The rest of his votes consist of either voting the obvious target (D2: Spaceman and D4: Takhisis) or not committing (D1: Bladescape). The most interesting vote of all is the D3 late run made on Autolycus in an attempt to save townie Coyosis, but I have no idea what to make of this. Feels townie, but I could see scum doing this to look townie.

All in all, he's been very careful not to look scummy. Too careful in my view.
Possibly Winston Hughes. Day One, tied the KM lynch by unvoting choxorn and voting Snerk. Granted, the votes totals in question are 2-2, but still the point stands. On Day two, while apart of the Newyn/spaceman flip-flop-a-thon, his last vote broke the tie by flipping off of spaceman and onto Newyn, resulting in a 5-3 Newyn lynch. However, before the original deadline had Newyn in the lead before Snerk's vote tied it. Newyn claims Winston during day three as most likely to be town (exact words are 'closest I have to lock town.') Plus comes back and explains his reasoning with how he voted on day two. Only mask connections consist of the day four voting of the Ornate and Shadow masks to each other.
My personal Scum'o Meter
(TM); patent pending, with 10 being a lock for scum to 1 being a lock for townie and 5 being split in the middle:
Newyn: 10
Winston: 7
Legato: 6
Snerk: 3.5
Visorslash: 2
Autolycus: 2
@ Newyn, who posted during this monstrosity. The sword in day three is Sprig's own sword. It's death by magic, as Awnshegh uses his own sword against him. Plus Sprig was a Knight, so... yea.