Interesting article here, regarding fairy tales.
But in the first sentence, is the word “auteur” misused?

Conventionally I'd say yes but I can see it as an interesting usage extension. An auteur is, as I understand it, a film director who stamps his own mark on films to an extent where they become his films rather than the films of the writers or performers. I can certainly see how you MIGHT use a similar idea with people who retell traditional tales in their own styles and become, in essence, the originators of tales they didn't actually write.

With that said I think I am stretching the definition a bit too far and it's not a usage I'd be comfortable with.

Regarding the premise of the research reported in the article, I'm sure Carl Jung would have said, Of course!"

Agreed with Bob - it's an interesting extension.