wow. why is it that people associate long hair with being female? i mean -that is biologically essentialist and somewhat transmisogynist on top of being really upsetting in general.
personally i am femme and have had long hair, short hair, and shaved (bald) hair. because my hair is super thick, frizzy, and dry, i prefer it either long or bald - currently it's long. but i was no less femme when i was bald...and actually it was emotionally and physically an extremely affirming thing for me as a femme when i did go bald. specifically because my whole life people have attached so much meaning to my hair and i've felt a lot of pain and pressure because of it - shaving allowed me to let go of a lot of that bullshit.
but then again, a lot of folks might not think i'm femme enough since i wear jeans and t-shirts pretty often, too.
i henna my hair using body art quality henna powder mixed with lemon juice, and i use coconut oil to make it more manageable. i've never used chemical dyes over henna but if the henna and the chemical dyes are both good, your hair shouldn't fall out. however, because henna binds to the hair unlike chemical dyes (it's reallllllly permanent), you may have some weird color reactions if you try to dye over it. that's why i usually don't recommend henna to folks who are really into getting specific color results or who use chemical dyes a lot.