I'm almost done re-reading LW&W. I've read The Magician's Nephew and The Horse and His Boy. After reading Magician's Nephew I was under the impression that the witch in that book was the same witch that is in Narnia when we first meet Peter, Edmund, Susan, and Lucy. Is this not the case? It doesn't seem like it is at all and yet I seem to recall C.S. Lewis referring to her as the same witch while I was reading the Magician's Nephew.
Things that don't add up in LWW include things like the book saying that no humans have ever set foot in Narnia or that the witch has never seen a human before. This of course wasn't the case because Diggory was there and so were the cab driver and his wife who became the first King and Queen of Narnia.
Do I have to read the entire series to understand these inconsistencies or can someone explain them to me without spoiling the novels that come after?