From looking at the bible and its passages, it was Satan (the angel Lucifer) who was first to sin, not Eve or Adam. And while people say that Satan causes all sin, by posessing those and causing them to commit sin, this is not all true. There have been cases where Jesus has met and cleansed those posessed by demons, but most of all human sins come from within.
Looking at the case of Adam and Eve.
Eve commited the sin all by herself, she was not possesed at any time, Adam did not even meet the snake and was therefore also not posessed. But Satan did speak through the snake to bring out those hidden desires from within Eve which then lead to her commiting sin. They both sinned by there own will and actions.
So how does this relate to the topic of the Satan and Santa, well...
Let no one say when he is tempted, “I am tempted by God”; for God cannot be tempted by evil, nor does He Himself tempt anyone. But each one is tempted when he is drawn away by his own desires and enticed. Then, when desire has conceived, it gives birth to sin; and sin, when it is full-grown, brings forth death (James 1:13–15).
Drawn away by his own desires and enticed. One of the origin stories of Satan was that, as an angel of God, was enticed by his own desire to become higher than God due to his already almost perfect state, this created his sin from pride which was the cause of him being cast from heaven. Another origin possibility was that the angel Lucifer grew jealous of God's attention to humans and went to prove that God's creations could be corrupted by corrupting himself.
Both of these bring towards a certain trait of Satan: its not that he directly wants to create sin, its rather he would provide opportunities for others to become corrupted and commit sin. And what better time than christmas.
The original idea of christmas is good, give to those who have been good, warn those who have been bad.
But we are human: we have envy, pride, greed, gluttony, sloth, lust, and wrath. We wish for those things we can't have, we get jealous if someone gets something that we want, we get hateful when someone gives us a bad present, we want to have presents that we can show off to our friends. These are all our emotions which lead us to sin and therefore corrupt ourselves, either removing us from God's influence or proving Lucifer's point that we are corruptable.
But this is all just the beginning, while Christmas is just a single day, the time and effort expendature can be considered a labour of months. And while it affects those at all levels of society due to our own desires and expectations. In lower income suburbs, a toy car may be the greatest gift ever to a child. In middle income, that car becomes remote controlled. High income, it is a real car.
But here is a fun kicker, what does an over commercialised christmas lead to? Of all things, Greed. The innocent ideals of what Christmas is to promote; love, community, spirit, and all that, gets expolited in other innocent days as well: Valentines day, Easter, love day, birthdays, other holidays which anyone can celebrate. Have all become overcommercialised and strewn away from ideals, all because of the hidden desires of men and women. While the three wise men seem like the good guys in the story, did they predict what their innocent gifts would become? ([{or were there actions their own?? or a far reaching plan of Satan/Santa himself?????} sorry, my own conspiracy theory here. Coundn't resist])
The starter for this all, a jolly man in a red suit. The picture of kindness and innocence, hiding a face of hidden desire. The greatest good can hide the greatest evil, and christmas and Santa are perfect cover for Satan and his influences. And even if the original Santa was pure, his legacy has been influenced to a darker path.