“Haskafically- What’s the difference between these boys/ men?”
Chofetz Chaim has a central ideology that believes that they have the one right answer to all of the world’s challenges. Ner Yisrael does not have a distinct, singular hashkafa. Thus, what you said, OP, was right on – Chofetz Chaim are boys, Ner Yisrael are men.