YES i did answer this before but like, first off curiouscat is dieded so it's not like my answer is accessible ... but here!! and as a precursor, these are more just personal headcanons i personally entertain myself for fun. i love a whole wide variety of them and so i often enjoy multiple interpretations of each character, but these are the ones i mostly have entertained bouncing around in my head !! usually if its blank (ie nothing noted for their gender, for example) its because i can't choose rather than 'default to cis' if you know what i mean . like i often see them as sometimes cis sometimes trans sometimes more

Aira Shiratori - trans girl, bi
Kohaku Oukawa - trans guy
Tsukasa Suou - bi
Tori Himemiya - nonbinary
Sora Harukawa - nonbinary, ace/aro
Midori Takamine - bi, ace
Shinobu Sengoku - gay, nonbinary
Tetora Nagumo - gay
Hinata Aoi - genderfluid, bi, ace
Yuta Aoi - genderfluid, aro, ace
Mitsuru Tenma - hes just vibing
Tomoya Mashiro - nonbinary
Hajime Shino - masc nb, gay
Hiiro Amagi - doesn't know his gender or orientation yet and thats ok
Subaru Akehoshi - bi, poly
Hokuto Hidaka - poly
Makoto Yuuki - trans guy, bi, poly
Mao Isara - trans guy, bi, poly
Yuzuru Fushimi - aro, gay
Mika Kagehira - agender, bi
Arashi Narukami - trans girl
Ritsu Sakuma - gay
Koga Oogami - gay, bi
Adonis Otogari - bi
Souma Kanzaki - ace
Natsume Sakasaki - genderfluid, bi
Mayoi Ayase - agender, bi, poly
Jun Sazanami - gay, poly
Tatsumi Kazehaya - gay
Ibara Saegusa - trans guy, gay, poly
HiMERU - nonbinary, bi
Eichi Tenshouin - gay, ace
Wataru Hibiki - genderfluid, bi, ace
Madara Mikejima - nonbinary
Tsumugi Aoba - cis people.......... gay
Chiaki Morisawa - bi, ace
Kanata Shinkai - agender, ace
Keito Hasumi - bi
Kuro Kiryu - gay
Rei Sakuma - gay
Kaoru Hakaze - gay, genderfluid
Leo Tsukinaga - gay, genderfluid
Izumi Sena - transmasc nonbinary
Shu Itsuki - genderfluid, transfem, poly
Nazuna Nito - transmasc nonbinary
Hiyori Tomoe - nonbinary, gay, poly
Nagisa Ran - agender, poly
Rinne Amagi - bi
Niki Shiina - bi