First, I'll complain... I LIKE THE WHO'S WHO! It at least reminds me the details of Marvel Comics. (I'm a old DC fan.)
Second, AUGH! That chapter seemed short. When I made it to the end, my first thought was "That's it? What about the Tony vs Albus scene?"
I like Neville as a friend to Harry, although I would think that the two of them would be "training" or something. Think of it this way... Harry was surrounded by Superheroes so wouldn't he think that the habits they go through in life are "normal?" Not to mention, how often do you see a fat or anorexic superhero? Given all that, I would think that Harry would have a rather skewed outlook on what the human body type should look like and that he'd ought to push himself to meet it (even if he isn't even a teenager yet.)