So cats don’t really use visuals to tell what sex each other are, they go by scent, especially when they’re, you know, not all up close and personal with each other and this is obviously the same in warriors with how bluestar could basically smell rusty’s manliness SO i think how trans cats could work is that if a cat was born with “male” sex organs, they give off and produce the same or similar hormones and pheromones as she-cats
or obviously, in a trans tom situation they have “female” sex organs, but create hormones and pheromones similar to toms
or with non-binary or genderfluid characters they have a mix of pheromones and hormones
In this way, the cats around the trans character KNOW that they’re a she-cat or a tom no matter what their genitalia