Ofcoarse, out of all those quotes, the first one is obvious. From my understanding of the Bible, humans weren't created faulty, as they were perfect, but granted free will. They used this free will(along with Satan's influence) to disobey a simple commandment, not to eat the fruit of the tree in the middle of the garden. They sinned of their own free will, sin came from Adam, & thus sin entered into the world. Satan also was perfect, but with his free will, decided that he wanted people to worship him, instead of God. And, after scheming, he went down as a serpent, & spoke to Eve, etc.
If Adam & Eve hadn't sinned, they'd still be on the earth, perfect, living forever in a paradise. Heck, if atleast Adam had chose to love God, more then his wife, & not sinned with her, Eve would've died for her sin, but Adam would've eventually gotten another wife, because he remained faithful, & would still be on this earth(this might be where the idea of Adam having 2 wives, 1 bad, 1 good, came from). But, there's a time coming, when the wicked are wiped from the earth, & it will become a paradise, & most faithful humans will live in this paradise forever on earth(144,000 will be up in heaven with Christ reigning as king's & priests). Plus, I figure, we'll eventually start venturing to other planets as well, but that's more of a personal theory.