The thing with Sasha is so well done, I was creeped out by it the moment her voice changed, and yeah. *shudders* It's so similar to the second-guessing I do all the time with face blindness that it really scares me.

Yes! I saw a post somewhere from someone who'd registered the voice change (but not listened to the end-of-S1 credits) and thought it was one of those things you occasionally get where a show has to recast an actor and everyone acts like there's no difference, so they mentally retconned to "okay this is Sasha, this is how Sasha's always been" -- which is perfect for how the characters' heads are being messed with.