lol, well I noticed it’s a universal punish actually. 
I think all characters can hit Kazuya out of his wavedash with any crouching normal no matter if it’s a high or low. I was confused because I heard someone say that only low attacks would work so I thought only cr.lk and Sweep would hit but I was wrong.
it’s weird cuz like I said earlier I got hit out of an EX Stone fists…Can’t remember if it was the uppercut or the low kick>punch followup. Logic says it’s the kick>punch because you olny have one hit of armor on the EX stone fists, but I’m pretty sure it was the uppercut.
I dunno. In any case I’m having less trouble with the matchup as long as I teleport and windmill appropriately.
I made this a while ago but never uploaded it for some reason:
[media=youtube]mLJ96upi_s4[/media]
Random labwork vs Vega:
Punishing flying barcelona attack on reaction:
-nj.mp CH Cross Art or HP Gehosen xx Switch
-backdash, Super or nj.mk, s.mk xx Windmill xx Switch
-f.KKK tele (avoid), s.lp xx L Gehosen, s.lk, s.mk xx L Gehosen
-MP SUS (avoid), EX Windmill/Super
-Flea Stance, duck (avoid), Sling Headbutt, s.mk xx Windmill xx Switch
Punishing Sky High Claw on reaction:
-empty neutral jump, s.mk xx Windmill xx Switch
-bj.mk, s.mk xx Windmill xx Switch (bj.mk will cause a reset if done too early)
-EX Windmill/Super
-Cross-Cancel
Punishing EX Sky High Claw on reaction:
-empty neutral jump, Super
-empty neutral jump, dash, EX Windmill
-fj.hp, s.mk xx M Gehosen
-fj.hp, H Gehosen
-reverse Super
-Flea Stance, duck (avoid), Sling Headbutt, s.mk xx Windmill xx Switch
Punishing Rolling Crystal Flash on reaction:
-Raw Launcher
-EX Windmill/Super