Both of them could develop in terms of their relationship. The pregnancy can be a catalyst for them to communicate more openly, share their fears and hopes, and ultimately become a stronger couple. They may also develop a deeper understanding of family values as they are about to start their own family.
At first, their relationship could be strained. Logan may be scared by the news, and Rory might feel let down by his initial reaction. But as time goes on, they realize they love each other and want to make it work. They start going to prenatal classes together, and through this shared experience, they rekindle their love and build a stronger bond for the future.
To develop Logan's character, you could show his insecurities about becoming a father. Maybe he had a difficult relationship with his own father, and he's worried about repeating the same mistakes. For Camille, you could explore her fears of losing her independence. As the pregnancy progresses, Logan could start to become more confident in his role as a future father by taking parenting classes or reading books. Camille, on the other hand, could find a new sense of purpose in creating a loving and stable environment for the baby.
For Camille, you could give her a backstory that makes her pregnancy more complex. Say she has always dreamed of a big career and now she's not sure if she can achieve it with a baby. This adds depth to her character. Logan can be developed by showing his relationship with his family. If his family has strong opinions about the pregnancy, it can create internal conflict for him and show different sides of his personality.
Logan would likely develop from a carefree person into a more responsible one. He'd have to think about providing for Zoey and the baby. Zoey would develop more maturity as she prepares to become a mother, becoming more selfless in her decisions.
I'm not sure of a specific Rory and Logan pregnant fanfiction off the top of my head. You could try searching on popular fanfiction websites like Archive of Our Own. There are often many stories related to various characters and scenarios.
Another plot could be that they face some opposition from their families. But they stand together and fight for their relationship and the upcoming baby. They could also learn a lot about each other's values and priorities through this experience which will strengthen their bond.
During the pregnancy, Zuko might start to explore his softer side more. He could become more nurturing, learning how to take care of Toph and preparing for the baby. He might also become more protective, using his firebending skills to ensure their safety. Toph, on the other hand, could develop her maternal instincts early. She might use her earthbending to create a safe and comfortable environment for the baby, like building a special room or a small garden. As she goes through the physical changes of pregnancy, she also becomes more in tune with her emotions and the emotions of those around her.
Obviously Rory herself is the central character. Her partner, if there is one in the fanfiction, would also be an important character. For example, if it's a romantic relationship - based fanfic, her boyfriend or husband would play a big role in the story, like being there for her during doctor visits and helping with pregnancy cravings.
Their relationship could be a complex one. They may have had a history before the events of the fanfiction. This past could add layers to their current relationship. When they make love, it could be a combination of lust and a longing to be closer to each other on an emotional level. For example, they might have unresolved issues from their past that they are trying to work through as they engage in this new level of intimacy.
On the other hand, Rory might be heartbroken. She loved Logan, and this situation could shatter her. She could cry a lot and feel really lonely. But then, slowly, she might start to find strength within herself. She could remember all the things she's achieved in her life so far and use that to boost her confidence. She could start writing in her journal again, documenting her feelings about the pregnancy and her new path in life.