This is really a well done concept. A lot of stories have Harry either growing up with someone else or some random clan, or vampires and werewolves and the like, but most of them fall prey to any number of clichés that I'm not personally much of a fan of. They're not bad or unenjoyable, they just tend to be rather predictable. Yours, while not unpredictable is also not terribly predictable. If that's because of how many AU elements you have, or how many of JKR's plot points you fill in, I can't say, but it's still been an entertaining and interesting read to follow.
So you're doing a great job, and I hope you keep it up, and update soon. By the by, nice touch with the pen-name. =p
Later