1.) First of all, the word lesbian actually comes from the Greek Islands of Lesbos where she is born, as a slang term to describe female on female sexual and romantic relations. In fact, it wasnt even until the late 19 century where the word has the meaning it has now. I seriously doubt they(lesbian of lesbos) had any say in how their word is used in modern terms(especially since it's a heated debate of topic for the island to this day).

2.) Yes, her poems were about women but a woman who engages in consentful sex with young male lovers is bisexual in my book.

3.) You don't like the word homosexual but you're willing to use a word that was taken without consent from the natives for your own identity purposes? Como sea, if it helps you sleep at night.