As to the magic stuff,
1.) What, specifically, is prohibited by the words mageia and pharmakeia in the NT?
As far as I know anything that is labeled "Gifts of the spirit" (a long list, IIRC it's in Corinthians) is allowed- discerning of spirits, healing, gifts of tongues, and some other stuff that can be interpreted- and John speaks of AP as if it is not a bad thing, but an awesome thing, and he also says that anything you do "in Christ" is allowed. So IMO it's not the practice, but the intention that matters.
ps. For some reason, they specifically allow casting of lots by name in various places- I always wondered about that.

I think when it comes to prohibiting people from doing something, the psychology of the person doing the prohibiting says more than the prohibition itself.