One common theme is the growth of Sasuke and Sakura's relationship. The pregnancy often serves as a catalyst for them to become closer and more committed to each other. Another theme could be the idea of family, exploring how they will create a new family unit different from what they had growing up.
Well, it's possible that a fanfiction like that exists. The world of fanfiction is full of unique and unexpected ideas. Since Sirius is a character from the wizarding world and Lily is also part of that universe, and adding a Muggle element along with the concept of Lily being pregnant in a shop - like scenario could be an interesting plot for a fanfiction. You might start by looking through the tags and categories on fanfiction platforms that are related to these characters and concepts.
One possible theme is the idea of new beginnings. Their relationship has been through so much, and now a baby represents a fresh start. Another theme could be protection. Mulder will surely want to protect Scully and the baby from any harm. And there might also be a theme of family, as they are now about to become a family unit, which is a big change for them.
He probably reacts with a mix of emotions. Mulder is a complex character. He might immediately start thinking about all the implications, like how this will affect their work and their lives. He could also feel a deep sense of protectiveness towards Scully and the unborn child right away. His reaction might be one of those silent, but very profound moments where he just looks at Scully with a whole new level of understanding and connection.
Gajeel might be initially shocked. He could then feel a rush of joy and immediately start planning for the future, like thinking about how to make a safe and happy home for the baby.
There are fanfics where Sasuke is a bit more reserved in his reaction. He may not show extreme emotions outwardly but instead, internally he's filled with a mixture of excitement and fear. He might start thinking about all the responsibilities that come with having a child and how his life as a ninja will need to change to accommodate this new addition to his family.
They would likely become closer. The shared experience of expecting a child would create a deeper bond between them. Vegeta might start showing more affection towards Bulma in his own way, like being more attentive to her needs.
First, you need to develop Lily's character well. Decide on her personality traits, like if she's a calm person or a bit of a worrywart when it comes to the pregnancy. Then, think about the setting. Is it in a modern city or a small town? For the plot, you could start with how she discovers she's pregnant. Maybe it was a surprise or something she had been hoping for.
One great lily pregnant fanfic could be about how she copes with the changes in her daily life. For example, she might have to adjust her work routine or deal with the various emotions that come with expecting a baby. Maybe she gets a lot of support from her friends and family, which makes the journey more bearable.
He might be initially shocked. Vegeta is a tough Saiyan, but deep down he has feelings. He could show a rare moment of vulnerability, maybe just standing there in silence for a while, trying to process the news.