Would Japan have built the B-65-style super cruisers, and how might they have been used?
Short answerPossibly if resources allowed; they could prompt an Alaska-class response and serve in surface groups with Japan's largest battleships.
NotesThe game design in the question matches Japan's planned B-65 super-cruiser concept. Japan might have wanted the ships if time and resources allowed, but those constraints prevented construction. Their appearance could strengthen the American case for the Alaska class. In service, they might operate in surface action groups around Yamato and Musashi rather than as isolated wonder weapons.