1) You are not asking for a reply on a message board, you are asking for a medical school textbook. I obviously cannot deal with every structrure in the eye, as it is one of the most complicated organs in your body. It is not, however, irreducibly complex, even by the standards of the man who invented the concept. If such hypothetical assumptions are not good enough for you, I suggest you take a look at one of the many thousands of organisms whose eyes, when compared to our own, are missing structures.
Here's one. Those spots on the left-hand side are the equivalent of your eyes, minus every structure except a little bit of the retina. Perfectly functional.
Here's another one. That's a very interesting one, actually. The eye of the nautalus is to your eye as a pinhole camera is to a Canon. There isn't any lens in other words.