usually when your moves are getting beat is if they stick out something faster than you. when that’s happening, he’s just pushing buttons hoping you’ll run into them. what you should be doing is let them push those buttons and make sure you stay right outside those ranges, then punish it while it’s recovering with a cr.mk combo or cr.mp, or even sweep.
for unique normals, cosmic heel tends to move you back in the first 6 frames, so you could use it when pressuring to avoid the crouch tech and nail them for pushing buttons. if it’s getting beat out, you’re using it too close.
overhead should be used at a distance. it’s as long as your st.mk, so using it at that range i think is optimal. once you connect with it, you’re not too close to be uncomfortable.
really need more details on what you can’t actually punish on those characters. too many to name
instant hk to keep him from jumping. walk back to make his jump in whiff. jump ins and pressure is vega’s weakness. avoid pressure by focus tech back dash.
hurricane kicks can be blocked if you block normal, then block crossup right after. why it works is that tatsu comes out slower. it needs practice, but it’s worth it. always use this kind of block agaisnt people with tatus. this tactic gets beaten by empty jump cr.lk though, so be careful if they actually found out you’re doing this type of blocking.
why can’t you hit seth exactly? what moves are giving you problems? one thing going for you is that he can’t do typical seth stuff, because you have the flip, avoids spd and dp. but that’s if he DOES get in. he will always try to jump and dive and stuff. instant neutral hk that shit. i know it’s hard, but develop the mind for it. watch the skies, not the ground. who cares if you’re getting beaten because you don’t have the reactions, at least you’re trying and practicing, you’re not in a real tournament. so just go for it. there are ambiguous crossup setups on seth you can do on him while he’s down so it’s not that bad.
seems like your main problem is just anti airs. we all have that problem. it’s vega’s weakness. you just need to train you mind to see those jumps and react to it with a instant neutral hk. i’ve posted this many times, but i’ll do it again, instant neutral hk+lp+lk. if you didn’t do the instant hk properly, air throw will come out, so it’s all good