For Chai at the you Arcade , buy Crawl Cyclone from Bunkado Antiques and level it up. During the fight, make sure your spacing is on point. Dont get too close to Chai, but also not too far. Spam Crawl Cyclone. When he slips through Ryos legs, immediately Hammer the A button. By kicking backwards, you can avoid a devastating combo from Chai. When he tries to go into his flying kick combo, punish him with a simple high kick, just pressing A, or even better, an Elbow Assault to send him flying across the room. Close in quickly and get in one or two cheap shots to Chais head with the Crawl Cyclone while he is down on the ground.
For Izumi: again, three things make the difference in this fight. Spacing, spacing and spacing. Keep your distance, use Ryos height advantage. When she comes in with her Sarah Bryant flying knee attack, evade to the side, or even better, behind her if you can. Then make sure to punish her. If you keep your distance from her, you will be able to mostly avoid her Sakura Festival attack command QTE and get your attacks in from time to time to eventually finish her off.