Third-round thoughts: The backstory between Arthur and Algernon Croaker sounds fascinating; might be worth fleshing out some time.
I wonder if Dumbles is every going to realize that Harry's manipulationg him through his occlumency shields? I imagine that will severely disconcert him, much like a lot of other things related to Harry will; not that he can do anything about it.
Author's response
It'll be background, but there might be some fleshing out...just a little.
Dumbledore cannot conceive of anyone being smarter than him. Ergo, nobody can manipulate him. Neat, huh? This is what we call circular logic. As he once said: "Isn't it amazing how nearsighted being invisible makes you?"
By the time Dumbley has the opportunity to try to probe, Harry, His studies under Carolyn's friends, will preclude his entry. He'll assume Harry actually did learn something from Snape, or found a guide in the Black Library, and berate his spy for allowing it to happen.
And nope. He can't.
Alorkin