1. That article from Chiff.com doesn't say the photos are authentic. It merely states that if it is true that someone received a copy before the release date, they could be real. I also read a few of the pages, and there's something weird about the way they're written. I guess we'll just have to wait and see.

2. I don't think Aberforth has anything to do with buying the stolen goods from Mundungus, but rather something to do with guarding Harry. Maybe Mundungus was filling him in on something? I still think the locket is at Grimmauld Place. It would be a reason for Harry to return there.