*This can be pronounced Ee-thee or Eth-ee, so that's nice.
I'm sorry about your dad. That's no way to treat someone, especially your kid, and he does not deserve to have custody. I'm happy that your mom is trying to get full custody, and I think that if Ashley would support you and keep it a secret for as long as you need to, then feel free to tell her. Of course, this is up to you, and if you are comfortable with telling her that you're genderfluid and you want to and are ready, do it if you want.
Welp. Names. So. . .
I have about ten million names for you. Personal favorites include: Onyx, Sparrow, Skylar, Riley, Asher/Ash, Fenyx, Felix, Kai, Reese, Sawyer, Bailey, Zephyr, October, Amethyst (SO MANY NICKNAMES 'Ethy'*, 'Ame'), Raven (I am obsessed with names like Sparrow and Raven, sorry about that-), Arden, Rowan, Emerson/Emersyn or Emery (nickname could be 'Em' or 'Emmy'), Everest, Wren, Remy/Remi, Sage (if you read my story, I really hope you know that it's one of my very favorites), Spencer, Finley ('Fin'/'Finn' or 'Lee' for short), Cameron/Camryn, Oakley. . .
*ahem*
And I have plenty more names that I haven't even covered yet-