My girlfriend mained Vega for 2 years so I’ve played that matchup until I was blue in the face.
Wall dives are easy to deal with: you dash then you DP then, or you focus then punish with EX danku. If Vega is doing the slash/grab mixup, you will have to dash or jump back and HK him.
I throw out a lot of HK dan kicks to close the distance when Vega is doing his pokefest / nj idiocy. Vega has NO tools to deal with pressure once you get in on him so get in ( and up) on him as scarlet terror has a crap hitbox above him.
Overall it is a pain in the ass because of his extreme mobility but you can hunt him down with dan kicks IMO.
I first dealt with it going against Zeus, but a lot of Vega players are getting out of Dan kicks with back jump fierce (instant overhead) makes it harder to apply pressure if I don’t have meter to make DP’s safe, then its back to chasing them down again, also focusing the wall dives just result in getting grabed. never thought of dashing the dp, trying to hope for an autocorrect dp on a hidden crossup istricky, only ex has a good autocorrect
higher level gameplay, the stuff you mention works, but not against people who know how to deal with that, I went against zeus in teams at winter brawl
Is it the regular one? Block it, low normal attack if you have good timing or go for Koryuken(hard version is good enough) if you have fast fingers.
Is it the EX one? Pray to the butt-clenching god of saltiness that you will survive this invincible, double-hitting, FADC-able, titan fist of destruction with inbuilt Fuck You bombs.
Basically, the Zonk Knuckle is really freaking good. Even tho it has a lot of start up, it also has a lot of upper body invincibility and it will smash your pressure game into pieces if used correctly. If the opponent understands your pressure game, he can throw out a EX Zonk and crush it pretty hard. However, all versions are unsafe on block, giving you a decent amount time for a comeback.
If you really want to bait this thing, use light normals. Zonk Knuckle can be used as a counter-poke, catching a lot of heavy pokes and even some medium ones. The good thing about Zonk is that it’s a charge move, so the opponent simply needs to release the button and the move will come out as fast as possible. I wouldn’t suggest to bait this move, but if you really want to I’m not stopping you.
Cody, in the end, is a pressure game tank with a lot of frame traps, damaging combos and a lot of options. He is Dan but better in almost every way. What he doesn’t have is a good wake up game and his backdash is horrible. EX Zonk Knuckle is his only good reversal.
So, yeah. All I can say now is be careful. Cody is scary.