Hey! Something else just occurred to me.
Adam and Eve were sinless before the fall. I thought that they were sinless because they did not know the difference between good and evil. Eating from the tree of knowledge of good and evil made sin possible. One of the requirements of sin is that the sinner knows that it is a sin.
If we look again to St. Thomas, I love St. Thomas

, he tells us that natural law is the study of natural evidence to determine God’s intention or will. Furthermore, St. Thomas tells us that all sin is a corruption of natural law because it goes against the will of God.
Along with Jesus and Mary, Adam and Eve were without original sin (up until the time that they sinned). Perhaps the reason that Adam was sinless is not really because of a lack of knowledge. It was more because of an inability to consider sin. If Adam and Eve were without unconscious, perhaps they were unable to get a notion of sin. Prior to the fall, all things complied completely with natural law. Sin was virtually impossible because sin is conveyed through the unconscious.
The temptation of Eve was not a mental temptation. It was a physical appearance of Satan. Again, as with the temptation of Christ, Satan was not able to work mentally as he does today.
I am liking your idea that Christ had no unconscious. I am also liking the idea that the unconscious resulted from the fall. As far as the unconscious being dark and the conscious being light, it is a metaphor. Does it help to explain how the conscious can overcome the subconscious?
St. Thomas gives us methods of subordinating the lower faculties. Basically, it is through grace, mortification, and prayers.