Most likely not. 'Murder in the Thirst' stories are often made up to engage and thrill the audience. They might draw inspiration from real events but are not strictly true.
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.
I don't know who the author of 'the great thirst novel' is. There are so many novels out there and without more information, it's difficult to determine the author.
I'm not sure specifically as I haven't read a novel named 'the great thirst novel'. It could be about a character's intense longing or search for something, perhaps water in a literal sense if it's set in a dry or arid context, or it could be a metaphorical thirst for knowledge, power, or love.