Another scenario could be that Bella does something that endangers Jacob's family or the werewolf pack. This would make Jacob see her as a liability and develop hatred towards her. In some fanfictions, she might accidentally expose the werewolves to their enemies because of her association with the vampires.
Sure. There might be some new characters created specifically for this fanfiction. Maybe a wise elder in the werewolf community who gives advice to Jacob about how to handle the situation with Bella and the pregnancy. Or perhaps a human friend of Bella's who discovers the truth and has to deal with the shock of the supernatural world.
Bella herself might struggle with her identity. She has been so caught up in the vampire world before, and now being with Jacob, a werewolf, she has to redefine who she is and where she belongs. She may also worry about how her human family and friends will react to her being with a werewolf.
A dominant Jacob is usually in touch with his alpha side. This means he has a natural leadership quality. He can command respect from others in the fanfiction world. And when it comes to Bella, this leadership translates into him guiding their relationship in a way that he believes is best for both of them. He may be more confident and self - assured, which can be both appealing and a source of conflict in the relationship with Bella.
It would become more intense and complex. Jacob would be very protective, his werewolf instincts kicking in fully. He'd be constantly worried about Bella and the baby's safety.
Well, it could be that the plotlines in the Sam fanfiction are just not to Bella's taste. She might prefer different types of stories, and the ones about Sam are often full of elements she doesn't like, such as certain relationships or events that are depicted in the fanfiction.
An unexpected guest could be a human who has some sort of special ability to see the supernatural world but has been hiding it. This person could come forward at the wedding and reveal that they know all about the vampires and werewolves and that they have a message from a higher power about Jacob and Bella's relationship. It would be very unexpected as no one expected a normal human to be involved in such a way.
Often, they focus on the complex relationship between Jacob and Bella. The 'lemon' aspect might imply some romantic or passionate moments. They can explore different timelines and scenarios not fully explored in the original work.