The problem with your question is that it doesn't stand true for the fallen angels and Satan. God hung himself on a cross to ransom mankind. Scripture tells us specifically what God has ruled will be the end for Satan and his ilk. I noted before that I did not understand the question you were asking.
It is now clear that you somehow think Satan would be able to be redeemed. Where you get this from is beyond me.
You say, 'surely non of God's creation, including fallen angels..' I would have to direct you to Revelation, Daniel, etc who speak directly to this matter. The fallen angels and Satan are beyond redemption. God has already judged their fate. That is what seperates them from us in this matter.
I'd like a cite that specifically states this.
(I shudda read ahead!! ;^)