Since I don't know the exact 'little red monkey story', if it's a typical one, the main character is surely the little red monkey. Maybe there could also be its parents, siblings or some animal friends like a little bird or a squirrel.
The little red monkey is definitely a main character. There might be an old wise owl that gives advice to the little red monkey. And perhaps there are some other monkeys in the troop that play important roles, either as friends or rivals to the little red monkey. There could also be a big bad leopard that the little red monkey has to avoid or outsmart.
In the 'little red monkey story', the main character is the little red monkey itself. However, depending on the story, there could be other significant characters. For instance, a mother monkey who teaches the little red monkey survival skills. There might be a friendly deer that shows the little red monkey new paths in the forest. And there could be a group of naughty monkeys that the little red monkey has to deal with, whether it's joining their games or standing up to their bullying.
There is likely the little monkey as the central character. There may also be other animals like birds or squirrels that interact with the monkey in the story.
The main characters are the five little monkeys. And usually, there's also a mother monkey in the story.
If the 'little red flower story' is about a journey, the main character could be a traveler who comes across the little red flower during their travels. Along the way, they might meet other people or characters, like a local villager who tells them the significance of the little red flower in that area.
The main character is the little red engine. There are also the toys and good things in the train it has to pull.
The little girl is the central figure in the little red shoes story. And there are also some other characters like the shoemaker who made the red shoes. However, the little girl's story with the red shoes is what the whole story is mainly about.
If the 'little red children story' is a story about a group's journey, then the main characters could be the bravest or the most curious among the little red children. For example, there could be a child who is always coming up with ideas to solve problems they encounter during their adventure. And also, there might be an older child who looks after the younger ones in the group.
I'm not certain about the main characters in 'the little red pen story'. It could be a group of students who all have a connection to the little red pen. One student might be the one who always uses it, another might be jealous of that student for having it, and a third might be the one who accidentally breaks it and then tries to fix it. Or it could be a story about an artist who uses the little red pen as their favorite tool and the people they meet while using it in different locations.
The main character is surely the little red elf. There may also be other elves as side characters.
Grandma is also an important character. She is the one that Little Red Riding Hood is going to visit, and she gets eaten by the wolf first. Little Red Riding Hood is known for her red hooded cape that gives her the name. She is often depicted as a kind and naive girl. The wolf, on the other hand, is cunning and hungry, using trickery to get what he wants.
Since we don't have much information about the 'little red coat story', it could be that the main character is a girl or a boy who wears the little red coat. There might also be some supporting characters like the child's parents or friends.