I always thought Q was "questioning". I live in the "gay neck" of my city, which is otherwise pretty conservative, by CA standards. I have no clue about I, A, or U. Those are new to me. I will say that our queer comminity seems somewhat majority gay male. No clue about bi's, but I have heard of that tension before. We have some TS guys here, but I haven't noticed TG's, or any opinion of bi's, TS/TGs, etc.
"For me, it is far better to grasp the Universe as it really is than to persist in delusion, however satisfying and reassuring." - Carl Sagan