Can a story have more than one main character?

Yes. In fact, many stories do. Think about 'The Avengers' movies. Each superhero has their own story arc, powers, and personality. They all come together as a group, but individually they are also important characters. So, having more than one main character can add more depth and variety to a story.

Sure, a story can have multiple main characters. It's quite common, especially in complex narratives.

Yes. Multiple main characters or protagonists can bring a rich tapestry of stories. In 'Little Women', the four sisters - Meg, Jo, Beth, and Amy - are all important characters. Their individual dreams, relationships, and growth form the core of the story. The story wouldn't be the same if it just focused on one of them.

Sure, a story can have multiple foil characters. It depends on the complexity and scope of the narrative.

Yes. Some novels are designed this way. Like in 'The Godfather' series of novels. Michael Corleone is a main character, but so is Vito Corleone in different parts of the story. They both drive the story forward in significant ways, so there can be more than one main or protagonist character.

Sure, you can. Many authors have multiple story ideas and projects going on at the same time.

Yes. There's no hard - and - fast rule that limits an OC to just one canon story. An OC can exist in different narrative contexts, and as long as each story is recognized as part of the official or accepted version of the character's history, they can all be canon. For instance, in a serialized webcomic, an OC might have a backstory in one arc that is canon, and then in a later arc, new events unfold that are also considered canon for the OC, expanding the character's narrative in multiple valid directions.

Yes. Just look at superhero movies. Often there are multiple villains working together or separately to oppose the hero. It makes the hero's journey more difficult and the story more exciting.

Sure, a story can have multiple antagonists. It's not uncommon and can add complexity to the plot.

Sure. It depends on the author's creative choices and the nature of the story. Multiple prologues could provide more background info or build up suspense in unique ways.