Its a timing thing , the best thing I can tell you is to wait a bit before executing the parry. It is actually one frame slower than her mkx version so it's slower. So be patient and make reads . The parry should be able to counter most high attacks, the low parry is trickier. Also the ai can read parries very well , they work better on human opponents.
For the air grab I came across a jump kick combo but I don't find it practical and it's too circumstantial, honestly for me it's pretty useless since air control is a better option for both anti air and combos.
Create a custom and replace the air grab with something else you prefer.