1) "Invented" the subconscious?
Well, all right, I was being a bit flip. He was the first person to come up with the idea of unconscious thoughts and perceptions, as far as I know. So he "discovered" the subconscious. Although his arguments for it aren't very good, in my opinion, so he was more lucky than brilliant in that regard, I'd say.
2) What was Enkidu all about in the Epic of Gilgamesh?
I'm not sure what you mean there. Doesn't he represent, if anything, the dichotomy between civilised and uncivilised man (or something)?