tagging in from network: Honestly I think that would work fine? "Temper, brilliant tactician and bi" is barely even a type, let alone a personality, and are EASILY things that an actual brother and sister could share while being totally different people. Like "brilliant at tactics with a horrible temper" is the kind of thing that could easily get stamped on a whole family (the way my maternal family are "stubborn and hold a grudge" and my paternal family are "loud, argumentative and know-it-alls".