Questions while reading D'Aulaires'

So, I've been reading D'Aulaires' Book of Greek Myths to my son, and tonight, some questions occurred to me while reading. How do we treat the dreams that occur in myth and fairy-tale and literature? How are invented dreams related to/ relatable to "naturally occurring" dreams? What do we do with these created dreams, other than looking at their relationship to the other elements of the piece in which they are found?

And, while I still have my questions concerning the usefulness of analyzing archetypal patterns (What do we do with these, really? What "real" purpose does this activity serve? Is this meant to bring us to some deeper meaning or understanding of humanity, the world, or literature, or? etc.), how do we approach the origin of such patterns? Or do we? How do we account for their existence at all? What purpose do they serve? Can we ever get away from them? For example, Classical Greco-Roman mythology and the Bible have countless convergences. Does this mean that there is some kind of Ur-myth, Ur-story lurking behind it all?

Also, the term displaced forces many questions upon me. Is the "original" the proper place and the displacement improper or out of place in a negative way? If these stories are somehow central to our culture, civilization, or humanity, then from whence come the stories? Do the stories form our culture or does the culture create the stories? When is a story considered original or "placed" and what does it really mean to say displaced? What do we mean by place? I can't escape connotations of perversion (per-version?) and impropriety when I think of displaced, yet I can't help thinking that displacement isn't a bad thing. I'm confusing myself now.