I'm not sure if this feels like a fit for you, but if you are keen to have conversation which includes matters relating specifically to being LGB and/or T, I would consider starting either:
(a) threads on that topic, as they come up for you, eg, Under Ask a Mustachian a thread could be "being fired for being gay". This would draw people who have interest, experience, knowledge, advice, and/or sympathy. This might include some LGBT people, but may also include a straight lawyer that cares, justice advocates, etc.
(b) a Journal including LGBT in its title. This might draw the audience of other LGBT people, as well as straight or curious folks keen on learning about the LGBT experience as it relates to finances, etc. In that vein, some of us have something like "single parent" or "avid cyclist" or whatever in our Journal titles -whatever element of our being or life that we feel affects/dictates our finances the most.
A fair number of people on the forum identify as LGBT, but generally refer to this just when it comes up naturally in conversation and usually indirectly/casually. i.e., Sometimes a person is talking about the expense of dating, and we notice a reference to meeting people of the same sex. My very first PM was an apology on my part for assuming in a post that a certain member was a straight male. She had referred to her wife, and I had made an incorrect leap. She didn't say anything -I realized it myself, sent my apologetic note, and corrected my post. She was very gracious about it, and I've been more aware of not assuming I know anything about anyone that hasn't been explicitly posted.
As you hang out on the forum, you'll learn in a casual way who identifies as LGBT, who is in a straight relationship, and all sorts of other wonderful things.