I am not completely sure you understand what your learning from this. Some people have these abilities. Some are explainable, and some aren't. Aura reading is possible, but also very difficult. Witch however is not exactly the word I would use. Try Pagan or Neo-Pagan. There are great differences. Young children have the tendency to overexaderate the things that happen to them, but I can not say that about your friend for I do not know what she has gone through.
The ability that you refer to however is not gained through 'Witchcraft, Voodoo, and practices'. Some are just born with it. John the Apostle was. It was not a gift of God or any magic. He was merely born with it. It no gift of Satan either. You however do have good view on the children of the Human race. They do not have the capability of choosing. And a Demon can not take over them for they are still pure. Once older, they may lose the ability to ward off the Demon.
Tell me of your friend. What exactly has she seen, felt, and/or heard during her experiences. I may be able to help you.
By the way. Don't call it Witchcraft. It's a steriotype. A mean steriotype.