>>54646350Everstone lets you pass down the form of the Pokemon holding it, and if both parents are of the same Pokemon (a normal Zorua in a Beast Ball, and a fresh Hisui Zorua born from the DLC handout), each parent has a 50/50 chance to pass down their ball. So I just bred until I got a Hisui in a beast ball and went from there.
He showed up very early in the process, I'm glad I managed to get a 0 atk IV at least early on with the power bracer.