I don't know the specific main characters as I haven't read it. But they could be children, parents, Santa Claus - typical characters in Christmas stories.
Since it's a collection of Christmas stories, the main characters could vary greatly. There might be a young child who is on a quest to understand the true meaning of Christmas. Or perhaps an old man who spreads Christmas cheer in a small town. There could also be a family as a whole, with each member having their own role in the Christmas - themed events. Maybe there's a mother who bakes the best Christmas cookies and a father who decorates the house in a spectacular way. Without reading it, it's hard to say for sure, but these are the kinds of characters that are common in Christmas stories.
Not having read 'A Christmas Story Stories', it's difficult to name the exact main characters. However, in many Christmas stories, we often see characters like elves, who are busy in Santa's workshop making toys. There could be a mischievous reindeer or a kind - hearted angel. If the stories focus on a more human - centered aspect, we might find characters like a little girl who writes a letter to Santa asking for a special gift for her sick brother, or a boy who gets lost on Christmas Eve and has an adventure that leads him to understand the importance of family. There are so many possibilities when it comes to the characters in a Christmas - themed collection of stories.