There's no way to know for sure without reading the story. However, it could be a single protagonist, perhaps a middle - aged person who decides to visit the fair to relive their childhood memories. This person could then interact with different fair workers, vendors, and other visitors during their day at the fair, and these interactions could form the crux of the story.
I'm not sure exactly who the main characters are without reading the story. But it could be a young boy or girl who is excited to explore the fair. Maybe it's an old man who has memories associated with the fair from his youth and is revisiting it.
It might be that the main characters are the fair workers themselves. They could be the ones whose stories are told, like the ticket seller who has seen so many different people come through, or the ride operator with his own tales of the fair's excitement.
I'm not sure as I haven't read the story, but it could be a child and his or her parents. The child might be the one who gets spanked and the parents are the ones who do the spanking.
I'm not sure without reading the story, but it could be a group of friends who are in a competition, like a board game or a race.
The main characters are Eliza Doolittle and Professor Higgins.
Not having read 'One Fair Day Graphic Novel', it's impossible to be certain about the main characters. But if we think about typical graphic novels set in a day - long event like a fair, we could expect a central character who drives the story forward. This could be someone new to the fair, full of curiosity. There may also be a character who provides some sort of opposition or challenge, like a rival at a fair game or a person with a different view on how the fair should be run. Additionally, there might be a mentor - like figure who gives advice to the main character during their fair - day adventures.
I don't know as I haven't read it, but they could be the vendors and the customers.
I'm not sure as you haven't given me more details about the story. But it could be a young protagonist, like a boy or a girl, who experiences something significant on this bright day.
I don't know as I haven't read it, but it could be students, teachers, or parents.
Since I don't know the story, the main characters could be a prophet - like figure who warns about Judgement Day, and the skeptics who don't believe him until it's too late. There might also be a group of leaders trying to maintain order during the chaos.