Most likely, the parents of the family from 'A Christmas Story' would be main characters. Since it's a prequel, it would make sense to focus on them.
The young versions of the kids from the original story could also be main characters. We could see how they were as children before the events of the 'A Christmas Story'. Maybe we'd learn about their early dreams or fears, and how they related to each other in those younger years.
There could be some new characters as well. For instance, the parents' friends or relatives who played a significant role in their lives before the story of 'A Christmas Story' took place. These new characters could add more depth to the backstory and help explain some of the family traditions or relationships that we saw in the original story.
I believe Rafiki could also be a main character. He's an important figure in the Lion King world. In the prequel, he might play a role in guiding the young lions or in the spiritual aspects of the Pride Lands. Maybe he knew secrets about the past that are relevant to the story.
Perhaps the main characters would be a family whose father or mother works at the clinker furnace. The children might be excited about Christmas while the working parent has to balance the demands of the job at the furnace during the holiday season. There could also be the furnace operator, who is in charge of keeping everything running smoothly during Christmas, and a local merchant who depends on the products from the clinker furnace for his business during the Christmas rush.
Well, obviously there would be the child writing the letter. And of course, Father Christmas himself. There might also be the child's parents or siblings who could be involved in the process, like helping the child write the letter or getting excited about sending it off.
There could be a new neighbor who moves into the town just before Christmas and brings a whole new set of Christmas traditions from a different culture. This character could add an interesting dynamic to the story as the other characters learn about these new traditions.
Wonder Woman herself is surely one of the main characters. There might also be some of her Amazonian sisters who play important roles in her backstory.
As of now, it's hard to say exactly who the main characters will be. But they will likely be members of noble houses or those with a connection to important events in Westeros' history.
The main character could be a reindeer that gets separated from Santa's sleigh. The reindeer then has to find its way back while having various adventures in the human world. Along the way, it meets different people who are either kind or mean, and through these encounters, the reindeer spreads Christmas cheer and eventually makes it back to Santa just in time for Christmas Eve.
It could be a baker. Bakers often play important roles in stories related to food, especially when it comes to creating a special Christmas treat like a creampie.
It could be a child who is excited about Christmas and has some big dreams for the holiday.
Probably common animals like a deer, a rabbit, a squirrel, or a little bird. Since it's a friendly animals story at Christmas, these are the kinds of animals that often appear in such stories.