Perhaps there are some business owners as main characters. They are trying to make a fortune in the boomtown. They might be running stores, mines or other businesses.
It could be that the main characters are a group of families who moved to the boomtown. They each have their own dreams and struggles in this new place. One family might be focused on farming in the outskirts of the town, while another could be involved in the construction work in the growing town center.
We can learn about the unique characters in the boomtown. Maybe there are brave miners or clever shopkeepers.
I'm not sure exactly, but it could be a child and his or her parent shopping in the supermarket.
I'm not sure without reading the story, but it could be the settlers who came to build the boom town.
They are often developed in a simple way. The characters usually have one or two main traits. For example, a character might be really friendly or a bit shy.
I don't know the exact characters without reading it, but it could be students, since it's a 4th - grade - level story. Maybe there's a smart and curious student, a friendly joker in the class, and a strict teacher who all get involved in the events of the story.
Probably the firefighters are the main characters. They are the ones who do all the heroic deeds in the story.
There could be a teacher as one of the main characters in the '3rd grade bicycles story'. The teacher might be teaching the 3rd graders about bicycle safety, or perhaps be involved in a project related to bicycles with the students. Another possibility is that there are a group of friends among the 3rd graders, like Jack, Jill, and Mike, who together form the main characters as they explore the world of bicycles.
The main characters are Cinderella, her stepmother, her stepsisters, the fairy godmother, and the prince.
Since I don't know the exact 'wolf 3rd grade story', it could be the wolf itself as the main character. Maybe there are other animals like a deer or a squirrel too.
I'm not sure exactly as I haven't read the story, but it could be the 3rd grade students themselves. They might be the ones having adventures in the library, like finding a mysterious old book or making new friends among the library shelves.