"I" "am (to be present tense)" "female" "changed (to change past tense)" "male" for trans for example (I really have no idea if this is how lojban works, I'm guessing)
Unfortunately, gender dysphoria and the transgender experience are way more complicated than that. It isn't that they are becoming a woman or a man; it is that they already are one but are taking the necessary steps to match their minds and their bodies.
Read Julia Serano's "Whipping Girl: A Transsexual Woman on Sexism and the Scapegoating of Femininity" and Antonio Demasio's "The Feeling of What Happens: Body and Emotion in the Making of Consciousness" for an introduction to the basic ideas involved.
And if that turns out to be a really long word then just shorten it like Esperanto's Mojosa (MOderna-Juna-Stilo, or Modern Young Style).
This does not work for Lojban due to its word-formation rules. Lojban requires what is called "self-segregating morphology", so any words that violate a certain pattern will wreak havoc on the rest of the grammar.
I don't really see how LGBT terms would be useful often however, I mean, if you go to a party and meet someone you would say "Hey I'm CardboardLamp", instead of "Hey I'm CardboardLamp, I'm a color of race, sexual orientation, age, etc etc etc", unless you're at an event specially held for LGBT members.
Most Lojbanic expression happens through text in the form of chatrooms and there are a lot of bisexual people in Lojbanistan, so it is only natural to include them.
And could you tell me what you mean by "retains mostly cis and heterosexual concepts despite known speakers"?
I am discussing issues of cisnormativity and cisgender privilege.
And is it not about cultural neutrality? It seems like you want it to be diverse,
You can't be culturally neutral without diversity.