Rereading Witherweaver:
The first thing of notice he does is presuring silver to reveal the reason for his fakeclaim. That's not a SK thing to do I think, since it puts attention on you and if silver was indeed mafia, gives them a reason to kill you.
He then continues to push Ichi, which is null, as he couldn't have known his alignment as scum. There's the whole "what will you flip" issue, which I wouldn't expect from a SK for similar reasons.
The beginning of D2 features WW going SK hunting, which is a scummy thing to do. Then he votes for Hydrad (due to PoE mostly)... I think that vote can easily come from a partner, there was not yet any danger of him being lynched. He presses him more strongly during the course of the game though...
WW's initial reaction to Ichi's claim is "I think I believe him". Mafia would of course know that Ichi is lying. And mafia doesn't want Ichi dead. Ultimately, I can see mafia!WW thinking "Hydrad is surely going down, better for me to push him hard". He would want his other partner alive though. Seeing his reactions to the mass claim will be interesting.
Okay, what do we have... he supports lynching Eevee to clear silver (which is good, as long as Eevee gets lynched, noone needs to lynch Ichi). But then, he settles on Ichi, which is a very dangerous thing to do. Of course multiple players thought WW was town, maybe he thought he could win on his own... but why take the risk? Okay, now he unvotes again. He then seems undecided for a long time, suspecting Eevee, silver, Ichi. Also tries to throw Jimmmmm into the discussion when people have settled on Ichi vs silver. He puts Ichi to L-1, maybe assumes he can't keep him alive without looking very bad the next day. After joth's intent to hammer, WW thinks about silver again.
The last thing to note is the WW/Ichi exchange after Ichi was lynched. This looks townie for WW, but could be Ichi trying to make his partner look townie.
In the end, I think WW is much more likely to be mafia than to be SK. Which means we lynch Eevee, and based on his alignment, it should be possible to find out who of ash/WW is the remaining scum.