Gosh, you are tough on the characters in these books! The things they think and do seem perfectly normal to me, even Ginny. I don't think Harry needs to change his behaviour or attitude; honestly I think he's fine as he is. Well, he could be a bit more insistent on getting answers to his questions - because then he could tell us! Once he does know what's going on he'll just naturally do the right thing in the circumstances like he always does ;D Mind you, he might already have murdered Snape by then.