Sorry for the wait, I’ll do my best to answer your questions.
- Dizzy is a very tough match for Baiken. To move forward, you can try dash-jumping (669) with an early j.HS when Dizzy is grounded. If it hits or is blocked, cancel the j.HS into an air tatami.
- I think you mean Dizzy’s s.HS and j.HS. 6P beats both of those attacks. If Dizzy is just jumping in with HS, you can 412P counter and then launch into an aircombo. Avoid the biting fish by blocking and using Baiken’s 412K counter. You might also try her Suzuran (63214K) to get through Ice Spikes/fish/needles. However, Dizzy can bait this and then go low to hit you out of the run.
Against other characters, use meaty air tatamis after a knockdown to keep them in blockstun. Then go high/low/throw to mixup.