Might be a House of M scenario where she's taken a town captive and somehow has a piece of vision which "technically" means he's alive, so she's using her magic to give the little that's left of him form. Agnes is obviously agatha - so maybe she's there to cause trouble - and in a chain reaction to her true intentions, wanda somehow bends reality as she snaps and a chain of events conclude with mutants being introduced to the MCU somehow wih multiverses of madness, maybe the phoenix force?
My thoughts about Vision are slightly different. I'm thinking that she brought him back the way you theorize but she unknowingly actually brought him back to life. He seemed like the only one actually questioning things and seems to notice something is up, where as Wanda wants all the things he is noticing to go away.
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