Greenjeans: Seriously, learn some combos, girl. That's the only advice I can give at this state.
Sei: Everything that Rei said is 100% useful, so I'll just build from there and imply that everything he said is valid.
Past what he said, learn 2/4 seal combos, particularly ones that end in 6C jD web d5C 6D, as I believe those will still be relevant (And SUPER important if they are) in CS2. (To see what that looks like, look at damn near any video of me from SCR, or Nezu, and you'll see it). Learning FRKZ would have been a great idea considering how overpowered it is at the moment, but since CS2 is coming so soon I would put off learning it til it is a brand new start. Learn some gimmicks/nuances too(2A cross under, odd command grab set ups, frame traps) and bumper mix up/oki (ending certain combos with d2B 623B d6B 2C (optional bumper) is very very strong, especially for certain characters like Hakumen and Rachel.
Lookin good though. Use 6B more, unless I missed you using it. Using 6B off 5A and tick grabs off 5A BOTH SPARINGLY is what makes 2A unblockable in America.