You're going to need to provide a specific example of the way in which 16th century demonology 'warped orthodoxy', or was intended to 'disprove the source of witches' power'; I've read Bever's article (albeit a while ago) and I don't recall him arguing for either of those points.

I think you're working from a few misconceptions here. The term via negativa doesn't really make sense in the context you're using it; it's a way of coming to know God by knowing what He is not.

Also, don't forget that not all of the writing about witches was being done by Catholics, as the Protestants wrote an considerable amount as well; two of the most important English works on witches, the Discovery of Witchcraft and of course James I's Daemonologie were written by Prostetants.