I should have read more carefully. Apparenty G.K.Rowling is borrowing from Greek mythos, but he seems to associate these names as being Wicca.
Thanks for the corrections. :-) I forgot about Draco being a constellation, too... but yeah, you're right, she does seem to be borrowing from Greek mythology.
Still, he copied & pasted from the website I gave the URL to in another one of my posts (which I suspect is a hoax just like the book Satan's Underground...) without even bothering to check up on the facts.