But if she tels Evelyn or Rachel instead of keeping it to herself the relative strength of the black mail could dwindle rapidly.
Yes, if Ashe were to confide in her mother or sister about the texts, I'm sure that they would keep her from going along with any blackmail, if blackmail is indeed what's behind the texts. But I think that it's just as likely and just as believable that she would keep this hidden from them. Maybe that would even be a player choice?
On the one hand, Ashe knows that her mother and her sister love her (though she wasn't sure about her sister for a while, because of the big fallout), and she's used to relying on her sister in a lot of ways, or was used to it before their estrangement. She ought to know that she could trust them with such a problem, and that they would probably give her good advice.
On the other hand, Ashe went a full year without telling her mother about the trouble between her and Rachel, and only confided in her when the situation became too much for her to bear. And she might not want to bring Rachel into something like this when they've only just begun to rebuild their relationship. And we've already seen that Ashe isn't the best at handling her problems in wise ways.
It could go either way, or it could come down to player choice. We have to wait to find out.
And once she start telling people like Fiona to start, telling the rest becomes easier.
If you mean that Ashe telling Fiona about being a duplo would make it easier for her to tell others the same thing, then I don't agree. The fact that her mother and sister know and still love and support her hasn't made it any easier for her to tell Fiona. And every additional person who is in on the secret is one more possible information leak which could expose her. So I think that it would be the same difficulty each time she tells someone new, unless Ashe somehow becomes less worried about the general public finding out. I think that, for each person she considers telling, she'll have to weigh how much she trusts them, and what the pros and cons of them knowing might be.
But I could be wrong about that.
But an interesting question is how much of that does the black mailer know. If they know how unstable Ashe currently is, that means they are close to her, and then yes they know how strong their threat is. If not, then the whole bagage of social stigma caried by being a known duplo becomes important. So if the black mailer is not so close and the social aspect of the revelation is weak ( week? not my first language) then the threats are not strong. There is quite a few points where the strength of the threats can weaken. I agree that Ashe's first reaction might be panic sprinkled by a lot of irrationality.
Yes, how much the blackmailer (if it's blackmail) actually knows about Ashe is an interesting question, as is the question of how they know.
That being said, I don't think that they really need to know much about her, other than the simple fact that she's a duplo. They might just be banking on the assumption that no duplo would want to be exposed as such. It's already been stressed to us in the story that most people have a low opinion of duplos, and the developer made a point of showing Ashe and her mother watching a news report about such an exposure leading to a suicide. This emphasizes for us the seriousness in this world of being outed as a duplo. And Evelyn urged Ashe to come to her if she was ever "not okay". That was almost certainly foreshadowing for the developing situation.
My point of not making the black mail too big and not making it too major of a branching path is simply because it could affect the development of the game in a serous way making it way longer than it needs to be... For Eruption Imminent ( the dev can do what they want) I hope the structure is a bit more linear to tell a more complet story. That is why I hope the black mail is not so great.
Any branching path in a game creates additional work for the developer, which means more development time. There's no denying that. However, the developer has already told us that the plan is to have at least some branching paths and to allow player choice to impact how the story develops. And we've been told that one such choice will be coming up in the next update. So this matter has already been decided by the developer.
However, the developer did say "... as long as the story doesn't suffer from it and I can keep the different threads at a manageable scope." So branching paths in the story will be included, but limited to what the developer considers manageable.