A few things:
1) This game had an update, but to an average player, the update are mostly background improvements and unlikely to concern most. The only notable change is the default Margin Time (the amount of time before garbage sent is increased) for Fever, which was set incorrectly.
2) I was wrong about Lagnus being the same character as Schezo: Lagnus has a "Harrassment" characteristic, which is shared currently by Maguro. This basically means that the character have a higher power on a lower chain, making sending low chain garbage most effective. Moreover, Lagnus' AI is different from Schezo in that he moves slower. Though with that said, Hed and Suketoudara are the same character essentially, even doing their first-instinct chains by filling up the bottom 4 rows.
3) Risukuma is surprisingly tough, as he has the same AI as Carbuncle, who moves rather quickly.
4) AI for Puyo Puyo is overall better than Puyo Puyo Tetris, and Rulue is most affected by this: her AI is not as powerful in PPT compared to here, where she had the second-hardest AI.
5) AI difficulty for Quest characters are lower, as both Hartman and Alex are not that tough, especially compared to the characters they took after (Lemres and Ms. Accord respectively) where their AI is one of the best.
6) Because Harpy replaces Yu & Rei, I will never touch that Fever moveset since I dislike Harpy's cacophonous shouts. Seriri is fine because I liked Ocean Prince's moveset enough to use her.
7) Tournament mode can only be done in multiplayer (at least 2 required), which is a pity as I would like there to be an option for the single player. At least you can play 8 players with just 2 controllers, though.
8) I haven't delve into online as a NSO is required, which I am planning to do next year when I get it.
9) Finally, replay functionality is awesome: you can skip to the best parts if you want.
Thank you for reading.