Opening the rook file, people think that's an advantage, but it just really is not, and will end up being far more of a liability later. As for d-pawn missing = gambit, gambit implies you have some kind of long term compensation for what you are missing, and you clearly do not in this case so describing it as a gambit doesn't really make sense. Missing the d-pawn though would be far more of a liability than the h-pawn as if you've ever studied chess at all, I'm sure you know how important central control is in the early game, and missing a central pawn puts you at an insane disadvantage in that regard.
I disagree with this. I don't see how an open rook file would not be an advantage.