His best friend could be a main character. Maybe his friend is like a side - kick in the 'game' of his life, always there to help him with quests or give him advice that's like hints in a game.
The Christmas story in Luke tells of the birth of Jesus, including details like the angel's announcement to Mary and the shepherds visiting the newborn.
Luke's friends from the light side could also be important. Characters like Leia, Han Solo, or Chewbacca. Their reactions to Luke's turn and their attempts to bring him back would be significant aspects of the story. There could also be new characters created specifically for this novel, perhaps some Jedi who were thought to be dead but are actually in hiding and oppose Luke's new path.
At first, it could be quite rocky if they find out later in the story. Percy might be angry that Luke has been keeping secrets or has done bad things in the past. But eventually, they would likely grow closer as they realize they are family and start to support each other.
For Katie, she could be developed by giving her more complex emotions. For example, instead of just being a meek character, she could have moments of great strength and determination. Maybe she has a secret dream that she's been too afraid to pursue until she meets Luke. Luke, on the other hand, could be developed by showing his insecurities. Despite his seemingly confident exterior, he could be afraid of not living up to his family's expectations. Their relationship could then be a journey of them helping each other overcome their respective fears.
For Katie, I could see Zendaya. She has the ability to portray a strong - willed yet vulnerable character, which would be perfect for Katie. As for Luke, Timothée Chalamet would be a great choice. He has that boyish charm and can bring out the kind - hearted and somewhat naive side of Luke that would be expected in a Cinderella - inspired story.
Michel could be one of the popular characters. He might be giving his very sarcastic yet endearing comments about the baby. And Taylor. He could be trying to enforce some town rules regarding the baby, like making sure the stroller is parked in the right place or that the baby doesn't make too much noise during town meetings. His over - the - top personality can create some interesting interactions in the fanfiction.