Rebekah's family has a long history of complex relationships. Her mother, if still around, might see the pregnancy as a way to strengthen their family's position in the supernatural world. However, some of her siblings like Kol might be jealous or feel left out. On Stefan's side, his vampire nature might make his family worry about the implications of having a half - vampire child. They would be concerned about how to raise a child in their world of danger and secrets.
Their friends might be really shocked at first. Some of them could be overjoyed, like those who are always rooting for Matt and Rebekah as a couple. However, there might be a few who are skeptical. For example, those who know about Rebekah's past might worry that she's not ready for motherhood. But overall, most of their friends would probably come around and offer support, whether it's helping with baby preparations or just being there to listen to their concerns.
Elena might be a bit shocked at first but then would be very supportive. She would offer her own experiences and advice, even if they are from a human perspective. Bonnie could be worried about the magical implications of a vampire pregnancy and offer to use her magic to keep an eye on the baby's development.
Their friends' reactions would be a mixed bag. Some, like Matt, who is more on the human side of things, would be in awe of this supernatural pregnancy. He'd try to understand it from a human perspective and offer practical help like getting baby supplies from the human world. Meanwhile, the other supernatural friends would have different reactions based on their own agendas. For example, some witches might see Bonnie's pregnancy as a powerful event and either try to use it to their advantage or protect it out of a sense of duty to the witch community. Overall, their friends' reactions would add a lot of drama and support to the fanfiction story.
One possible plot could be that Stefan and Rebekah find themselves in an unexpected situation where they are about to have a baby. There could be a lot of drama as they deal with their families' reactions. Maybe the Mikaelsons are initially against it, while Stefan's friends are also shocked. They would have to navigate through their own relationship issues while preparing for the new life coming.
The Mikaelson family, especially Klaus, could be antagonists. He might see the pregnancy as a threat to his family's power or reputation. He could try to stop Stefan and Rebekah from being together and having the baby.
One possible plot twist could be that the pregnancy is a result of a magical spell gone wrong. Maybe a witch with a vendetta against them cast a spell that made Rebekah pregnant with Stefan's child as a way to disrupt their lives. Another could be that it's a false pregnancy caused by some dark entity preying on their fears of starting a family. This would add a lot of drama as they first deal with the shock of the pregnancy and then the realization that it might not be real.
Sirius's friends, like the Marauders, would be extremely shocked. They would probably be very concerned about Sirius as they know his feelings towards Bellatrix as an enemy. They might try to convince him to break away from the situation, thinking it's some sort of dark plot against him. James, in particular, would be very protective and would want to figure out what's really going on.
Tessa's family might be overjoyed at first. Her mother could start knitting baby clothes right away and her father might start planning how to convert a room into a nursery. They would offer a lot of advice based on their own experiences.
Gunther's family might be overjoyed. They could be very traditional and start preparing all kinds of old - family - recipe baby foods right away. Cece's family, on the other hand, might be a bit more cautious at first, but then quickly warm up to the idea and start knitting baby blankets.
The Stark family would likely be horrified at first. Sansa's father was beheaded by the Lannisters, and there is a long - standing feud between the two houses. Her brothers, if they were alive, would be very angry and might see it as a betrayal. The Lannisters, on the other hand, would also have a mixed reaction. Cersei would probably be furious, seeing it as a threat to her power and influence. Tyrion might be more understanding and could potentially try to mediate between the two families.