I think it inconsequential to faith if there was an actual Adam and Eve.  The absence of these two characters does nothing to eliminate the concept of Original Sin.  It is similarly inconsequential to assert, as Kenyon, I believe, that Jericho was destroyed in the Middle Bronze Age by Thutmose III or, as Wood has it, that Jericho IV gives clear evidence of the veracity of the Biblical account.
Inspired is the right word - the truth isn't the historicity of Scripture but what the stories tell.  Whether myth, allegory, morality play, or apocalypse the stories are not "mere" forms but tell of something deeper.  
To say, "If 'Adam and Eve' did not exist, neither did their 'sin'" is like saying, "If Aphrodite did not exist, love does not exist, either".  Myth may simply be used to explain a truth and the absence of the mythical character does nothing to what lies beneath.