Are you really accusing Quix, of all people, of trying to limit what the Holy Spirit will and won't do in a Believer's life? Seriously?
As for the OP, I'd have to say that while it's Biblical that every Believer has authority over demons, in practice it's a whole different matter. It's not so much the fact that some have a gift over others as much as most Christians today, in America at least, aren't what you'd call "Spiritually Aware" of their surroundings.
While there may be nothing technically wrong with what these girls are doing, I think that it's incredibly foolish and dangerous to give people the wrong idea in this matter. Exorcists absolutely must be strongly rooted and grounded in their faith and while I don't doubt that these girls may believe strongly in what they're doing, I have a hard time believing that they have developed a strong Gift of Discernment yet.