Perhaps the story could take a really dark turn. With Bella dead, the Volturi might see this as an opportunity to assert more control over the Cullens. They could come to Forks under the pretense of investigating Bella's death but really be there to intimidate the Cullens into following their strict vampire laws more closely. Meanwhile, Jacob could struggle with his own identity and his role in Bella's death. He might feel like he failed to protect her, and this could lead to him making some rash decisions in his werewolf form, endangering not only himself but also his pack.
Edward would be completely shattered. He might lose all sense of purpose and even consider ending his own existence. Jacob would be filled with anger and grief. He might blame Edward and the Cullens for not protecting Bella. Charlie would be heartbroken and would likely be in a state of shock for a long time.
One possible development could be that the relationship between Bella and Edward becomes even more complex. Edward might feel a stronger sense of protectiveness towards her. Also, it could lead to a rift between Bella and Jacob, as Jacob may not be able to handle the situation well. The Cullen family would also be greatly affected, having to deal with a pregnant human in their midst.
One possible plot development could be that his friends are left to pick up the pieces. They might struggle with grief and guilt, thinking they could have saved him. Another could be that Voldemort finally takes over completely without Harry to oppose him, leading to a dark reign over the wizarding world.
Another direction could be that they focus on building a normal life within the vampire world. They might start a school for other vampires or hybrids, teaching them how to co - exist with humans. Edward could use his knowledge of music and literature, and Bella could share her experiences of being human - turned - vampire.
The other demigods at Camp Half - Blood would also be in chaos. Percy was like a leader to many of them. His death could lead to a lack of confidence among the younger demigods. Some might even start to question the protection of the gods. Zoe's survival could also lead to her taking on a more prominent role in guiding and protecting the demigods, which is a big change from her previous situation.
One possible plot development could be that Bella's job as an exotic dancer draws the attention of the vampires in Twilight. Maybe they are intrigued by her confidence and allure in this new role, which could lead to new and different interactions compared to the original story.
One possible plot development could be how the wizarding world reacts to the loss of the so - called 'Chosen One' even as a baby. There might be widespread grief and fear among those who opposed Voldemort, as they had placed so many hopes on Harry. Another aspect could be how Voldemort's reign of terror continues without the threat of Harry Potter. He might become even more powerful and tyrannical, with no one to oppose him in the way Harry was prophesied to.
One possible plot development could be that his death shatters the Straw Hat crew. They might disband in grief, each going their own way. Zoro could become consumed with revenge, vowing to take on the Marines who were responsible.
One possible plot development could be that Bella starts to learn more about Alice's past in a very detailed way. They could bond over shared experiences and in the process, Bella becomes more like a sister to Alice than just a friend. This could lead to some interesting situations where they protect each other from various threats in the vampire and werewolf world.
One possible plot development could be Bella trying to find a way to escape the forced marriage. Maybe she discovers some hidden secrets about Edward or the circumstances that led to the forced union, which gives her leverage to break free.