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For the first two, it seems like a minor pedantic point so I'd chalk it up to a simple continuity error rather than retcon.
That third example is arguing with itself, basically saying "Work is trope X, except maybe not, maybe it's trope Y". I'd just cut that example under Examples are not Arguable.
I didn't choose the troping life, the troping life chose me

WandaVision and WandaVision Episode 8 "Previously On":
Retcons are deliberate changes while error is unintentional so these seem mutually exclusive. I'm leaning to the backstory being a Retcon as it's changing a minor, relatively unimportant detail replacing it with something major and important to the plot. Not sure about the Vision one. Thoughts?