Princess Bella is obviously a very important character as she is the one going into labor. Her partner or husband would also be important as he would likely be there for support.
We might expect a lot of drama and emotion. There could be a focus on the support system around Princess Bella, like her family and friends. Maybe there are midwives or healers helping her through the process.
Peeta is surely an important character. He has a deep connection with Katniss, and he would be there to offer emotional support. Her mother, being a healer, would be crucial in ensuring a safe delivery. Also, Haymitch could be there. He has always been like a mentor to Katniss, and he might use his experience to help in any way he can.
Obviously, Bella is one of the main characters. There might also be the teachers or students at Sky High like Will Stronghold or Layla Williams.
Caroline Forbes is another character. As a vampire herself in Mystic Falls, she could either befriend Bella or be jealous of her presence. Caroline is known for her strong personality and her relationships within the vampire community.
Obviously, Edward would be deeply impacted. He has dedicated himself to Bella, and her new evil nature would force him to reevaluate their relationship. Jacob, who has always been in the mix with Bella, would face a great deal of turmoil. And don't forget Carlisle and the rest of the Cullen family. They have accepted Bella into their family, and her going evil would be a major threat to their way of life and their values.
In the fanfiction, it's very possible that Puck would be at Quinn's side during labor. He has a history with her and would surely care about her well - being. Her best friends from Glee club would also be around. Rachel, with her big heart, would probably be there offering words of encouragement. Finn, being a good friend, would also show up. And Santana, who has a strong bond with Quinn, would be there to give her strength and sass when needed.
Bella's best friend could play a crucial role. They could be the one who stays by her side throughout the process, providing emotional support, bringing her things she needs in the hospital, and even arguing with the hospital staff if they think Bella isn't getting the best care.
The caretaker of the orphanage could be an important character. They could be either very strict and cold, creating a difficult environment for Bella, or they could be warm - hearted and act as a parental figure to her.
She might meet Aro, one of the leaders of the Volturi.
She might meet her younger self. It would be an odd yet fascinating encounter, as she could see how she used to be and compare it to who she is now.