Obviously Jacob is a great choice. His friendship with Bella always had the potential to make Edward jealous. Then there could be a new vampire, like a very sophisticated and handsome one who takes an interest in Bella.
A charming human guy from school can also be included. He could be the popular jock type who is not afraid to show his interest in Bella. And maybe an old acquaintance of Bella's from her childhood who resurfaces and is very friendly with her.
Alice could be a great addition. She could use her ability to foresee events to help Edward and Bella avoid getting caught by the police. Another good character would be Carlisle. He could be the voice of reason, trying to convince Edward to turn away from his criminal ways. Jasper might also be included, perhaps using his power to influence emotions to help in certain situations.
Well, the main characters are obviously Bella and Edward. Bella is the one who tries to make Edward jealous, usually by getting close to other male characters. Edward is the one who gets jealous because of his deep love for Bella.
Jacob would be a great character to include. He has a strong connection to the family, especially Renesmee. His werewolf nature could add an interesting dynamic to a crossover story. Also, Carlisle. His wisdom and experience as a vampire could be useful in different situations in a crossover. For example, if the crossover is with a supernatural world that has different rules about vampires.
One idea could be Bella starts spending a lot of time with Jacob, and she makes sure Edward sees them having fun together, like going on hikes or working on Jacob's car. Another could be that Bella flirts with a new vampire in town in front of Edward.
Alice is often a great character in such fanfiction. Her ability to see the future can add a lot of twists and turns to the story. For example, she might foresee a danger to Edward and Bella's relationship and try to prevent it.
Edward is an obvious choice. As the father of the baby, his role is crucial. He can be portrayed as overprotective, or struggling to understand the new situation. Jacob could also be included. His relationship with Bella is complex, and his reaction to her pregnancy could add a lot of drama. Then there's Carlisle. As a doctor - like figure in the vampire world, he can offer medical advice and support during the pregnancy.
One aspect could be that in such fanfiction, jealousy often adds a new layer of drama to the relationship between Edward and Bella. For example, if a new character is introduced, and either Edward or Bella shows jealousy, it can lead to interesting conflicts. It might also explore their insecurities within the relationship more deeply.
A new character, a kind - hearted artist in the town, could be a great addition. This character could be the first to truly understand Edward's artistry with his scissorhands. They could collaborate on a project that changes the way the town views Edward, bringing more acceptance and new opportunities for him.
The Cullens from the Twilight series are obvious choices. They could interact with Harry in various ways. For example, Carlisle's medical knowledge and his calm, father - like presence could provide stability in a dangerous situation that Harry and Edward find themselves in.
Maybe Bella goes to a party and dances with a lot of other guys. She acts really carefree and happy with them, ignoring Edward. This would make Edward seethe with jealousy. He might start to question their relationship and become a bit more withdrawn, which in turn could make Bella realize she's gone too far.