Transgender people are people who are not comfortable with gender roles and cant really be defined with a loveual orientation.
HOWEVER!!!!, this does not excuse renaming yourself and pretending to be a girl.
If he is as confortable with himself as he claims to be, then he wouldnt need to pretend to be someone else.
so in conclusion:
He is NOT transgender/bi whatever the forget he wants to call himself, in any way. He is just trolling, pretending to be someone he finds more enjoyable then his sad real self. and we should all treat the friend as such.