Against Jean, his main BnB comes in his delay strings and wall-hits. If your on a small walled stage (platform on the lake), for example, Jean can walk over Shun all day long. Shun really needs room to work, so playing to the long end of the stage will come to an advantage. You do have a benefit in that you have plenty of tools to punish his more fancy attacks (delay anything turns into a free 66P+G) but he can take off drinks like crazy with his dashing punch, which I believe robs 1 or 2 on the spot every time. Your best chance is to wait for him to lose that long-leg advantage (against good Jeans, easier said than done) by closing in and guarding when he delays his strings or goes for something with decent recovery time. Though you’d have room to land your 1PK, I find its better to get in his face and pressure him. Jean’s biggest flaw is he has a horrendous time dealing with pressure. Close the distance and keep on him, moreso make sure you keep yourself either outside of his range or deep inside of it. If you get caught at the sweet spot theres literally nothing you can do as Shun.
Brad I find a bit easier in that he has some obvious sound cues to when he is hitting and when he is bobbing. Listening is more important than reading or leading since Brad, in all honesty, is probably the hardest character to read when he is on the offensive. Once you hear the “shh” storm die down, thats your best chance to hit them.
Against Pai, you haven’t got much luck but she is hella easier to deal with than eileen. Learn the opponent’s openings and how the react, it might take you two rounds of losses to get it down. However, her tools are very limited in comparison to Shun, so eventually you’ll know all of her tricks and the timings. Against Lau, its all about building habits in the opponent by doing the leading from earlier. Lau’s wake-ups are usually boiled down to wake-up into knockdown, or tech into guard, both of which are easy to walk over.
Jean - Get in his face or out of his range, but avoid the sweet spot. He has a weakness for direct pressure, and with Shun there should be no shortage.
Brad - Learn to listen for the audio clues to when he stops, and hit him in that short span. It’ll be a match of bursts, so don’t be afraid to go all out in your combos to achieve the maximum amount of damage. Pressure in short spans, and remember Brad’s main high-low are pretty visually obvious. Use all the tools you get.
Pai - Make her use up her tools and learn fast. Its a match of adaptation, and luckily for you Shun has more moves and between cancels he will likely not run dry.
Lau - Lead him all day, and learn how they like to wake up.