Harry didn't check his visitors to see if they were imposters, but they didn't check him either... which is odd for Moody, especially considering he noticed his behaviour is very different.
too bad you say it's probably going to be Harry/Hermione... not a pairing I like personally. it has even less basis as the Harry/Ginny thing.
who and what is the person who is hanging around? I take it he's related to Harry somehow? will the Gringotts visit have something to do with it?
hope you'll continue soon!