Dottie can produce facts about his genitals. He has looked up enough on Wikipedia to know that he has most of what people would expect externally from both men and women, both below and above the waist, and will go into exactly as much detail about that as people want to hear. It's- maybe not possible, here, he hasn't actually researched intersex condition in depth. Presumably not every random user of a casual sex app is an expert on human biology when it comes to edge cases like this. If no one bites, that's fine; he mostly wants to measure the spread of reactions. He takes notes about this on his phone.
As for the history of the eclipsed- no major insights, although he doesn't think he's been correcting enough for just how much oversight eclipsed must get. They develop powers at such a young age, and if they indulge in the kind of impulses children have five times a day, they can turn into fonts of destructive power. If chanters were that dangerous alone, they'd need more supervision. Instead- just cut one of them off from people, and you've got the perfect prison.
Dottie really does not want to go to jail for the rest of her his life, which is probably a distinct possibility. All he has to do to avoid that is be so useful to Isabella that she can't replace him with an identical chanter without this particular problem- which will be trivially easy, once she decides to do it. So. What does Dottie have that no other chanters have? What can he do that no one from Chant can do?
One, he's one of the best chanters of Exile in her district. It's not the most impressive rank- not the best in her country or state or the country, but- best in the district. It's not nothing. And if she can get better- if she just wants not to be in jail badly enough, she has something nearly unique to offer. She'll just need to figure out how to spin it so that Isabella wants it.
Two, he's an omega. There's a cause here, for people who want to champion it. If he tells Isabella to help him go to bat for omegas, then his involvement with her on a charitable cause will keep him safer.
Three...three. If he's Isabella's type, there's a third option there. If there's a personal connection there, maybe she would keep him as her personal omega. He has no idea if he's her type, but lying is not really a good way to find out. If he knew how she would react- well. There's a way to do that, isn't there. He need to co-chant Gift with her again. There are limits to how pre-cogs work. He looks for a Wikipedia article about how precog works.