Fall: How could an Angelic Fall effect the Fall of mankind?

• An Angelic Fall can be posited to explain a Fallen creation.
• This is deemed necessary because the Theory of Evolution requires 'fallen' characteristics of the natural world in order to explain the development of species on Earth today.
• In this scheme the Fall of humanity was a human failure to live up to the redemptive role given humanity in a Fallen Creation.
• Death would obviously have been used in the creation of humans, but the first truly human pair were offered immortality.
• But, why is there a relationship between the Fall of Angels and the corruption of Creation? To affirm this link would be to affirm some sort representative role to the angels so that their Fall affected the rest of Creation. There is then a form of Original Guilt which Creation lives under, both of the Angelic Fall initially and then of the Human Fall, which failed to redeem Creation.
• If an Angelic Fall resulted in a corrupt creation, what can be made of the Biblical witness to a Creation that was 'Very Good' before the human Fall? (Gen. 1:31)
  
• Further, does an Angelic Fall solve the Problem of Evil?
• Of course not, it simply raises the question as to why God created beings who he knew would sin?
• The Plantinga-Mackay debate can be rehersed here.
• Plantinga's Transworld Depravity, seems to me not to work unless we say that all Angels fell or at least will sin some time in the future. Such a statement seems overly speculative (!) although to be fair to Plantinga, his defense was merely intended to logically refute proofs against God's goodness or existence from the Problem of Evil, not actually provide a theodicy.