There are two primary schools of thought in regards to the genre of Job.
One the one hand, some call it an historical artifact, given no overwhelming evidence to the contrary.
On the other, its position in the Writings could mean that it never was intended to be such a thing, but rather was intended as a creative work of fiction.
The question is, which position is the older understanding of its genre?
From Wikipedia, Book of Job:
The Talmudic tractate Bava Batra (15a-b) maintains that Job was written by Moses, although nowhere does it name its author. Other opinions in the Talmud ascribe it to the period of before the First Temple, the time of the patriarch Jacob, or King Ahasuerus. The Talmud cites a number of opinions about exactly when the events of the story happened, including one opinion claiming that Job “never existed and was never created; it is a parable,” without specifically adopting any one stance.
The attribution of the book to Moses follows Rabbi Yehoshua ben Levi, ca. 200–250 CE; so the rest of the debate dates from some time later. This is likely the earliest attested discussion of the pedigree of Job, and as you can see, many of the positions you mention are already recorded.
