A fascinating read. I'm very aware of the Lilith mythology, and it makes for a great story (indeed, I may well borrow the idea of Lilith for one of my future novels). Do I believe she was real? No idea. I have my doubts, despite the vague allusions to her in Isaiah that you mention.

As a Christian I do believe in a literal Adam and Eve (they have genealogies in the Bible after all, unlike, say, The Good Samaritan, which was a parable told by Jesus). However, there's a lot of ways the Book of Genesis can be interpreted (for example, there could be millions of years passing between certain verses in Genesis chapter 1). I don't get too dogmatic about any of this. For me, the important message is that Jesus came to save all humanity from sin, to reconcile us with God. Whether the Earth is millions or thousands of years old, or whether Lilith was left out of the Bible, or even existed at all, is a secondary (but fascinating) matter. :)