In reading this thread I wonder if part of the problem lies in a false dichotomy between true/false, fiction/non-fiction, history/mythology. I wonder, as has been brought up before, if the Hebrew people would consider the history/mythology of Genesis to be a valid question. I will try to explain by comparison to Lakota tradition. Please forgive the rambling! I hope this is on-topic, I think so.
In traditional Lakota (Tetonisa) story-telling there was fiction (wakankanpi), non-fiction (woyakapi), and a third category called ohunkapa. The latter correspond most to the word parable. These are stories of heros and gods that are meant to shed light on the nature of the Wikan (~Great Spirit). Unlike Western mythology these stories were often invented by the story teller. If Christians followed this tradition they would go to church and hear the pastor telling a story of how Jesus was pulled over for speeding or some such thing with the message being to illustrate some truth about his nature.
The deities in the ohunkapa tradition are considered "real" in that they represent true aspects of the world but their existence as individuals is a topic for discussion with the outcome irrelevant to the "truth " of the story. I hope that made sense! So you could ask a shaman "Did Gnaski really try to kill the gods?" and he could give you his opinion on whether or not it is historical. BUT the story itself is true because it frames the relationship between man and his control over the natural world. The story also is about if wisdom is subjective.
So say I were to climb into my time machine (I am building it in the garage out of an old vacuum cleaner, I found the plans in a copy of Popular Mechanics I took from the dentist's office) and go back, say 2,500 years ago and find myself a Hebrew priest. If I asked him is Genesis literal or figurative would the answer be yes/no? Or is the question laden with a dichotomy that wouldn't mean a whole lot to the priest? In a history of the Bible class I took as an undergrad we discussed whether or not King David was real or mythological. The professor made the statement that it didn't matter to him either way because the story is about God's covenant with believers (then and now). That is ohunkapa!
™ Version 4.2