Hi Anna, yes, the second link of theories lumps together L.G.B. And, the second link also includes a ‘transgender emergence model.’ (I haven’t investigated)
The first link which is a study includes L.G.B. sexual identities. Some interesting findings there in a small sample:
So, basically, I had to look in two places to bring together most of the alphabet. There may be more out there! I ran out of time. Hope others will chime in too. Thanks for reading and responding!!