A.B.A. takes recoil damage from everything she does to you in Moroha (key rape) mode. If she transforms from key rape back to normal mode via that damn key grab throw move, she gets 80% of that back. 120% if she transforms back to normal via a bloodpack. So, step one against A.B.A. is to not let her do that. Keep the pressure way up so she doesn't have time to throw a bloodpack, and try even harder than usual to get knockdowns. Whatever you do, knock her down. A lot. Three knockdowns before she has a chance to transform back = a penalty forced transformation that gives her 0% damage back and has a huge open window in the animation. (Characters like :KY:, , can even IK charge and Instant Kill her during that, though Millia's IK takes a little too long to get out. Still a free gold burst, Winger, 2H --> combo, or whatever else you feel like doing to her, though.) My favorite trick against A.B.A. is roll or turofall --> throw --> Tandem Top (H) or Secret Garden. If you're not good enough at input to reliably chase a throw with an air combo that leaves her on the ground, just letting the throw go still nets you one of the precious knockdowns and enough time to throw a Secret Garden or Tandem Top (H), which can lead to guessing games on her wakeup which will hopefully net you another knockdown.
Danzai and its Hammerfall-like armor has the potential to eat your attack string and turn the momentum around if she catches you with it, but if you anticipate it and are open to blocking, block the first hit of Danzai, roll, second hit whiffs, throw. Good times.