-Haruka: Demisexual. He was completely neutral about dating when he was little, didn't want to get a girlfriend (though he was incredibly close to Aya, more than he is now and that's why Kujō thought they were dating...), he just didn't feel like he wanted to date girls, but he also didn't feel like he wanted to date boys when he learned that was a possibility. It was after he started to get closer to Zool that he started to think about dating them specifically.
Touma: Bisexual. He always was way more into women, so each time he felt attracted to a man he thought it was normal and that everyone felt like this too, after all he likes women so he must be straight!! But after he got into No_mad he started to have feelings for Hiroto and also realized that thinking his bandmates were sexually attractive was weird... He had a crisis but after that just accepted he's bisexual.
-Minami: Gay. He has always known he's into men since he was a child. He was always more invested into his male co-workers and male cartoon characters, it's only when he was a little older that he could understand what that meant.
Torao: Bisexual leaning more towards men. He had an inkling if it for quite a while but always felt ashamed of it, he has a lot of internalised homophobia (😔) so denied all of it with the "being gay is a choice" mentality. Then he got into Zool and couldn't deny his feelings anymore... He's still learning to accept himself + other's so he's not as judgemental as he used to be.