I don't think Rowling is quite as sophisticated theologically as Lewis, but I would agree that, so far at least, her outlook is basically compatible with Christianity. Just start with the fictional hypothesis that some people are endowed by inheritance with magical abilities, and she treats this endowment much as a Christian would treat endowment with talents.
If God gives someone great talents, of intelligence, strength, quickness, these talents can be put either to good or evil use. But talents are good in themselves. Similarly, if you had magical powers you could use or abuse them. The good people in Harry Potter play games with magic in a spirit of joy, or use them beneficially. The evil people seek power.
Pullman's books are basically Gnostic: the creator of the world is evil, there is hidden knowledge known only to the initiate, knowledge is power, and so forth. I wouldn't be surprised if Rowling drew on Pullman in portraying her villains. A recent review suggests that she also drew on the great duel between Hitler and Churchill, displaced for a while by the appeaser Neville Chamberlain. Hitler, of course, was also saturated with ideas about dark magic.