I'm not sure. It could go either way. Sometimes characters come back in unexpected ways in manga. Maybe there'll be a twist that brings Gojo back into the story.
At the moment, it's unknown if Gojo will come back to life in the manga. The storyline could take various turns and surprises are common in manga. We'll just have to wait and see.
Sure, Gojo came back to life in the manga. It was a surprise for many fans and was handled in an interesting way. The author crafted a storyline that made his return plausible and engaging.
I'm not sure specifically which 'two shots of vodka back story' you're referring to. It could be someone's personal experience of having two shots of vodka and what ensued, like maybe it led to a wild night out or a memorable conversation at a bar.
One possibility is that it was part of a drinking game. People took two shots of vodka as a forfeit or as a part of the rules. And this led to some interesting interactions among the players, like friendly banter or even some new friendships being formed.
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.