This is for those who know what “death of the author” means or who is willing to look it up, but in short, it can summed up to mean “whatever a work of fiction means is up to the people to decide on”.
Question inspired by an incident the other day where I saw someone one day cite “death of the author” when asked why he went into the womens’ bathroom, saying “you keep saying the symbol on the door is a stick figure in a dress, but I look at it and see a stick figure in a cape, and so I entered because I’m super.”
Those are all interesting questions that, like you said, generally do not admit clear answers.
For art, maybe there is a related question. Should analysis of an art piece (be it text, music, visual, etc.) also analyze the artist, or, put another way, is understanding the artist important to understanding their art? I, personally, like to say that the artist, in general, usually distracts from the art. But this is in many cases untrue.