My view is 1) in a way, 2) no, 3) read on!
Consider two snapshots in time.
- No humans around yet, just plants, animals and so forth. Lacking free will, they have no
moral responsibility, and the concept of "sin" makes no sense.
- Humans exist. We have free will, moral responsibility, and conflicting tendencies: we are born to trouble (as sure as sparks fly upward, Job 5:7), but we are also loved by God and are drawn to him, since we are formed in his image.
The creationist viewpoint is that between 1 and 2 came the events of Genesis 1:26 through 3:24, as literally described. Evolutionarily, what took place is that humans evolved from our animal ancestors, gaining self-awareness and the ability to make moral choices. Unfortunately for us, that means that we can choose poorly. I read the story of Eden as a narrative exposition of this basic problem of the human condition.
So for your question 1, I think of the Fall as historical in that between step 1 and step 2, we fell; but not strictly as described in the Genesis story.
Our tendency to be tempted (Genesis 3:1), the resulting disobedience to God's will (3:3) and the desire to take his place (3:6) have resulted in our shame (3:7), alienation from God (3:10, "I was afraid"), from his creation (3:17-19), and from one another (3:12, Adam blames Eve). We had to wait for the promised seed, Christ, to defeat sin (3:15). By following him, we can regain the eternal paradise that had been denied (3:22-24).
These facts do not depend on there being a specific couple, Adam and Eve. Now, it's possible to counter this by pointing to passages like 1 Corinthians 15:21-22, which in the NIV reads
For since death came through a man, the resurrection of the dead comes also through a man. For as in Adam all die, so in Christ all will be made alive.
How can we view Christ as the new Adam, if there was never an old Adam? Actually, the literal interpretation has a problem in that Genesis 3 doesn't pin all the blame on Adam: Eve was tempted first, and they both ate the fruit. So I think that Paul has to be speaking figuratively in any case, using Adam as the stand-in for all of humanity. In the same way, there is Romans 5:12-21, saying that after the first sin of the first man, we are all sinners, but now we can all be redeemed through Christ. This redemption doesn't come about through physical descent, so I don't see a reason to say that we sin only because we are descended from a sinner. To me, it makes more sense to believe that Paul was speaking in a midrashic way about Adam, and that sinfulness is inherent to our (present) human nature, than to impose a literalist view on the text.
But whether or not the Genesis account is taken literally, from step 2 onwards, we are in the same spiritual and moral position. As Don Marquis put it in archy hears from mars,
[earth] is in charge of a
two legged animal called
man who is genuinely
puzzled as to whether
his grandfather was a god
or a monkey
i should think said mars
that what he is himself
would make more difference
than what his grandfather was
not to this animal i replied
he is the great alibi ike of
the cosmos when he raises hell
just because he feels like
he wants somebody to blame it on