Animal spirits and animistic stuff may have demonic influences, but it is not exactly capital-S "Satanic". For better or for worse, forms of animism have coexisted with Christianity in many cultures, even Orthodox ones. I'm not saying it's wholesome or entirely blameless, but the Church has shown that there are positive aspects mixed in with the old religions, and that there is truth in there, even if obscured by error. The work of demons is real but so is the fact that the creation reveals to us the Creator; the veneration of many peoples of the world for nature led them to some knowledge of God. Simply saying, "Oh, they are demon worshippers and that's that" is not helpful and, in my opinion, not consistent with a Church whose saints have found value in Plato and Laozi.
Now, coming to your situation- I don't know the specifics or the people involved, but I do live in PA. When I hear some teenager in PA talk about seeing "animal spirits", the first thing that comes to my mind isn't "Uh oh, Satanist!" Unless he's a Native American, it probably means he's been hanging around the "metaphysical" section in Barnes and Noble, between forays into the woods in search of fairy circles. Can this be dangerous? Sure, but it's probably a phase; if the girl says she doesn't do it anymore, it's probably true- she likely got bored with it and moved on to something else.
Pray for them. Whether they would want you to pray for them, or whether they desire God's help, isn't relevant. We should pray for all.