Wavedash back and uptilt
Tbh it's only effective if the puff is over-committing. If the puff just pokes at you then you're **** out of luck, though puff can only really get off combo's if she guesses & follows up a bair, but if she would be safe about them there isn't a whole lot that can be done.
My main strat vs puff is to just wavedash toward her and shield a lot...at the very least I push her to the side of the stage and force her above me, where I can actually punish. Aside from that I charge my ball lol. Also I light shield and make them chase me as I slide across the stage, since they have to move in more you can start hard shielding and nairing/ubing out of it
I have more of a problem with bair gimps. But yeah better DI would at least help lol
Your grapple should get you safely back onto the stage, is he bairing when you grapple? Be sure to maximize the time between when you air dodge, and when you actually hit the grapple. A lot of times they'll just attack your air dodge, and you can grapple safely once their hitbox is gone. Or if you are sure they are going to hit you, air dodge, then get hit w/o using your grapple. I do this quite frequently when I know I'm going to get hit.
Also I forgot who asked this but, as far as frame data for the CC jabbing
You jab, 18 frames later you press Crouch, then on the very next frame you let go of crouch and can press A for another jab
one MOREEEEE thing, UB renders you INVULNERABLE on frames 1-5 of the move. Just a reminder.