Toge Inumaki is important too. His special cursed speech ability makes him stand out. Also, the principal of the school, Masamichi Yaga, is likely to be important as he is in a position of authority and has an influence on Gojo and the other students. There could be other characters like the members of different clans that also play roles in the complex web of the story.
The 26th and 27th episodes of the second season of Celebration of the Year were the series of the TV series. In the 26th episode, Fan Xian blocked the Qing Emperor's mouth so that he could not go back on his word. Wu Zhu seemed to want to take Fan Ruoruo as a disciple. In the 27th episode, Fan Xian fell into the Second Prince's dangerous situation. The Second Prince tried to force Fan Xian to lower his head by threatening his relatives and friends. However, the details and development of the plot still needed to be understood by watching the series.
It's hard to pinpoint exactly where Gojo is at any given time in the manga. His whereabouts change as the story progresses and different scenarios unfold. It could be in a supernatural realm, a mission site, or interacting with other characters.