You're right -- Aravis doesn't sound Arabic to me, either, and doesn't quite fit in with all the other Calormene names. Well, Aravis, herself, didn't quite fit in with most folks, either, did she? :)
I think *The Horse and His Boy* is my favorite of the Narnia books. Not that I've read that many, mind you. In fact, I think that maybe I've only read *The Lion, the Witch, and the Wardrobe* all the way through, besides *The Horse...*.
I will agree with you that they are great books. And that's quite a compliment to C.S. Lewis, coming from a Satanist such as myself. ;)
-- Nanaea