Feige also said this was the series where Wanda gets the name "Scarlet Witch," and they've already set it up with that clunky scene where they establish that she has no code name in the MCU.
I'm going to predict Agatha gives her the name, the Mind Stone unlocked her power to channel magic (if we're very lucky they'll call it "chaos magic"), but they won't retcon her parents because that's not Feige's style.
Schaeffer also said after episode 4 that we would get the story from Wanda's perspective, so I'm guessing episode 8 will fill us in on exactly what Wanda thought was going on.
I'm also going to assume Dottie is the one brainwashing everybody. They set up that thing where Abilash/Norm just said "she's in my head," and the only person who said it was Wanda was Agatha, who of course was faking it. since I don't think Agatha is doing it either that pretty much just leaves one other woman to pin it on, and the show hasn't exactly shied away from obvious twists.
Basically I think they'll try to set it up so that Wanda has been inadvertently helping the villain by refusing to face up to her grief and let it go, but she doesn't have as much control as she thinks she does, because Feige/Schaeffer are not as into character assassination as the comics.
Which is also why I predict Agatha will turn out to have been in town to help Wanda in her own sinister way.