After watching a few guides on how she works in various games, this is how I'd imagine Chun-Li playing:
Chun-Li's ground game is super strong. Her down and forward tilts being amazing pokes, with the heavy ones being safe on shield if spaced correctly. Assuming she's based on Street Fighter II, she'll also have a Marth-tier walk speed that allows her to repeatedly pressure shields with these pokes. At closer ranges, she can threaten opponents with her fast as heck neutral attack (especially if she's based on Street Fighter III: Third Strike) also probably auto-corrects because FGC. lol. Her heavy up tilt will also likely be a great anti-air.
Her air game will be a lot less potent, but she does have some unique properties she can take advantage of like the ability to wall jump, her down air that causes her to bounce off of opponents and their shields, and potentially, the ability to grab opponents in the air (though she'll probably immediately throw them like Isabelle does with aerial Fishing Rod).
In older games, her special moves are kind of just memes for the most part, so I feel like for them at least, Chun-Li will take inspiration from newer games. Kikoken is what you'd expect: A projectile that can be used in zoning wars, and light Kikoken is slower than the heavy version, allowing Chun-Li to walk behind it. Spinning Bird Kick will likely function similarly to the shoto's Tatsumaki Senpukyaku in practice, being primerilly a recovery move that can be comboed into in certain situations. It will be pretty terrible in neutral though. Lightning Kicks acts as both a pressure and combo tool, pushing Chun-Li back quite a lot on block so she can continue her pressure, and with other moves linking into it on hit. Tensho Kicks is her most obvious recovery option. The move would likely be added as a good out of shield option and a meh recovery move. They could use Hazanshoe instead, giving her an up and down style recovery, or they could do it along side Tensho Kicks, instead making it a move that allows her to hop over projectiles and stuff like Jolt Haymaker is supposed to.
TLDR: Chun-Li sets herself apart by having rediculous grounded pressure, even on shield wich is rare in Smash. She also has Kikoken and potentially also Hazanshoe to gain control of the match when her opponents are trying to zone her out, and some good anti-air and out of shield options when opponents try to pressure her. This all comes with the weakness of disadvantage state, as while she has some unique strengths in the air that can add depth to her offstage and air game, her recovery is still super linear, and her landings are easy to catch.