(this got long I'm sorry I can break it down separately!)
I headcanon the InoTanZen (in a QPR) all being nonbinary in very different ways: Tanjiro being genderfluid but in a way that's very contextual and sticking to they/them for convenience, but sometimes their partners can pick up on how they're feeling and sprinkle in a gendered noun to validate their current state.
Inosuke being agender but refusing to change from he/him pronouns because they're HIS and there's no sense in arguing. (Zenitsu tried once and failed) His partners find it easy to give him pet names based around nature so as not to imply a gender. Not that he really minds, his minions are the best!
Zenitsu being maverique (purely for the flag colors, I'm weak to pretty flags) and being fine with any pronouns but absolutely melting when anyone uses neopronouns for xem.
*IN TEARS* YALL HEARD IT!!
QUEERPLATONIC T4T INOTANZEN!!
I don't even!!!! Have words??? For how happy this makes me!!! Hajskaksjaahdjajs??? InoTanZen all supporting eachother.....im... I'm going to cry.............that's it ...jm sobbing...thats the answer..... cryimgg...