You asked about
> . . .the satan's plan thing... I'm not too
> familiar with Satanism, maybe you could
elaborate?. . .
According to LDS theology two plans were presented in the Grand Council before the world was made.
Jehovah (Jesus Christ) presented the plan of Elohim (Heavenly Father) which would give man free agency to choose right and wrong, allowed for the possibility of failure which would be an after-life judgement sending persons to the Terrestrial or Telestial kingdoms or Outer Darkness, but also included the possibility of Exaltation and godhood in the highest degree of the Celestial kingdom for the most obedient.
Satan presented his plan which would eliminate free agency on Earth but would assure that everyone would make it at least to the Celestial kingdom. Satan demanded Elohim's "honor" if his plan was accepted.
Jehovah offered to be our Savior and give the "honor" to Elohim.
Elohim accepted Jehovah's offer. Satan was mad his plan was rejected so he waged war with those on God's side. Satan and his side (1/3 of the total) were cast out of heaven. Those who accepted God's plan (1/3 or 2/3, is not clear) were permitted to take physical bodies on Earth according to the plan.
Some LDS argue that Satan's plan couldn't work as he promised it would. I've argued in the past that it could. Since, according to LDS theology, retarded adults and underage children automatically go to the Celestial kingdom after they die, all Satan had to do was make us all retarded.
Whether Satan's plan could produce gods is not clear. In the past I suggested that his plan might not produce gods, maybe that's why it was rejected.
It eventually became my opinion that Satan's plan was the better one. Who care's about free agency for a few short years of Earth life in exchange for a sure thing in the afterlife? Some LDS worry that if God had given His "honor" to Satan that would mean Satan would be God and things would go downhill for the universe very quickly. That could be bad.
This doctrine of the LDS and other religions that "underage children who die automatically go to heaven" is another example to me of the unjust things God would have to do to be the God people claim He is.
Thankfully, I don't have to worry now about God and Satan and who I will live with when I die because I've come to realize that they're just imagined beings passed down from our superstitious ancestors.
From an LDS point of view "Satanism" is different than what I've been describing. Satanism would be worshipping Satan and trying to use his powers rather than just arguing philosophically that his plan was the better one.
If anyone else has questions about LDS theology I will do my best to answer them, but let's remember this is a "God and Science" forum. Also, let me remind you that, as with all religions, not all LDS know their own doctrine.