There could be a character from one of the districts who was among the first to oppose the Hunger Games. This person might be a leader figure in the early resistance. It could also be a mentor - like figure who trained the first tributes. They would be important as they could show the different reactions of people to the emerging Hunger Games system.
There could be the predecessors of the Gamemakers. They would be important as they are the ones who design the Hunger Games.
It's possible that there will be a character who has a connection to the later main characters in the original Hunger Games story. Maybe a relative or someone who inspired them in some way. This character could be the center of the prequel's plot, and through their story, we can see how the events of the prequel lead to the situation in the original Hunger Games.
I'm not sure exactly as I haven't read it yet, but I assume there will be characters related to the founders or early influencers in Panem. Maybe some important Capitol figures or leaders from the districts who played a role in setting the stage for the Hunger Games.
Katniss and Peeta would probably still be main characters. Their relationship from the original Hunger Games could be further explored in the context of this new marriage - based game. They might have to deal with new challenges to their relationship, like how to balance their individual goals with the expectations of this new game format.
Maybe the protagonists will be a group of rebels. After the events of the previous books, there could be a new wave of resistance. These rebels might come from different backgrounds and have different motives, but they all aim to overthrow the Capitol. Their stories could be intertwined as they work together towards this common goal in the new Hunger Games novel.
Haymitch Abernathy is a key character. He is a former Hunger Games winner and becomes a mentor to Katniss and Peeta. President Snow is also significant. He represents the power - hungry and cruel leadership of the Capitol.
Finnick and Annie could also be featured. Their love story in the Hunger Games was very touching. A wedding fanfiction about them could explore their post - Games life and how they build their new life together. Also, Effie could be in it. She has a unique personality, and her presence at a wedding could bring some Capitol - style glamour and also some comical moments as she tries to understand the more down - to - earth district wedding traditions.
There could be the predecessors of the characters from the main game. Maybe the early versions of Six or the other kids we see in the original 'Little Nightmares'.
Miles Morales himself is sure to be a main character. He's the focus of the story. His family members, like his parents, are also likely to be important characters as they play a big role in his life and character development.
The main characters include Katniss Everdeen, a brave and skilled girl from District 12 who volunteers for the Hunger Games. Peeta Mellark, the male tribute from District 12, is another important character. Gale Hawthorne, Katniss' friend back in District 12. And then there's President Snow from the Capitol who is the main antagonist, trying to maintain the Capitol's control over the districts through the Hunger Games.