Both questions are favorite topics of anti-Mormons because presented out of context they are great attention grabbers and raise suspicion. Regarding question #1 I posted this on another thread:
I think it fair to say the LDS concept of becoming a god (little g) is similar to the Catholic doctrine of Sainthood. In other words, to us there is only ONE GOD (big G) but we can become “like” God, our Heavenly Father in some sense (little g). Christ said that his disciples would inherit “all that the Father hath.” However, what that means exactly is just speculation, not official doctrine.
Regarding #2, we believe that God (Our Heavenly Father) created everything, including our spirits. We believe Satan was a spirit son of God who rebelled.
11 How art thou fallen from heaven, O Lucifer, son of the morning! how art thou cut down to the ground, which didst weaken the nations!
13 For thou hast said in thine heart, I will ascend into heaven, I will exalt my throne above the stars of God: I will sit also upon the mount of the congregation, in the sides of the north:
14 I will ascend above the heights of the clouds; I will be like the most High.
15 Yet thou shalt be brought down to hell, to the sides of the pit.
(Old Testament | Isaiah 14:12 - 15)
25 And this we saw also, and bear record, that an angel of God who was in authority in the presence of God, who rebelled against the Only Begotten Son whom the Father loved and who was in the bosom of the Father, was thrust down from the presence of God and the Son,
26 And was called Perdition, for the heavens wept over him—he was Lucifer, a son of the morning.
27 And we beheld, and lo, he is fallen! is fallen, even a son of the morning!
(Doctrine and Covenants | Section 76:25 - 27)
9 And the great dragon was cast out, that old serpent, called the Devil, and Satan, which deceiveth the whole world: he was cast out into the earth, and his angels were cast out with him.(New Testament | Revelation 12:9)