Just a little history here. About two years ago, we had a trans meetup here in Ft Lauderdale.
When the venue was public very few people showed up, maybe 3 or 4. When we met at a private home, 12 or 13 people would show up. Some of the ladies needed a changing room, because they were not out to family or friends yet.
When the organizer became post-op, she went stealth and another lady tried to pick up the meeting. We had one meetup at a public place and only 3 of us showed up. Needless to say, the meetup folded shortly afterward.
Many of us then went to local support groups and we would go out to a local restaurant afterwards for a social hour.
Good luck with your meetup. One word of caution, if you meet in a private home, there are liability risks and clean up issues that must be considered.