Harry's friends would likely be shocked at first. Hermione would probably be the most practical, immediately trying to find books on male pregnancy in the magical world to figure out what to do. Ron might be a bit clumsy in his support but still be there for Harry. Harry's partner would be both excited and scared, constantly by Harry's side.
Harry himself would be in a state of confusion and fear at the start. He's used to dealing with dangerous adventures, but this is a whole new level of unexpected. His partner would try to comfort him, and as time passes, Harry would grow into his role as an expectant 'parent'. They would face many challenges together, like dealing with the judgment of some of the more traditional families in the wizarding world, but their love would keep them going through it all.
The teachers would have a mixed reaction. Some stricter ones might be appalled at the situation as it goes against the school's norms. However, Dumbledore, being the wise and understanding headmaster, would see it as an opportunity for the students to learn about love, responsibility, and the unexpected in life. The other students would gossip a lot, with some being envious of the deep relationship Harry has with his partner.
No, it's not a popular genre. Most Harry Potter fanfics tend to focus on more traditional themes like his adventures, relationships with friends and enemies, and his growth as a wizard. The idea of Harry giving birth in school is quite unusual and not something that appeals to the general fanfic - reading audience.
The teachers would probably be in a bit of a panic at first. They'd need to make sure Hermione and the baby were okay. Professor McGonagall would likely take charge, ensuring that proper medical care was provided and that the students were kept away from the area to give Hermione some privacy.
I'm not aware of many specific 'Harry gives birth in school' dating fanfic stories as this is a rather unique and not very common concept. However, you could start by looking on popular fanfic websites like Archive of Our Own or Fanfiction.net and use those keywords in the search bar to see if any relevant stories pop up.
Perhaps in this fanfic, Harry's pregnancy is a result of an ancient magic related to a deep emotional bond in their dating relationship. The story could revolve around how they balance their studies, their relationship, and the upcoming birth. They might seek help from a wise teacher who has knowledge of such rare magic.
Hermione would probably be very shocked at first but then would immediately start looking for a magical solution. She might rummage through her books to find spells to reverse the situation or make it safe for Harry.
Hermione would be devastated. She would initially think Harry had lost his mind. She'd probably try to find a way to rescue him, using all her knowledge and research skills. Ron would be angry at first, feeling that Harry had betrayed them. But then he would also start to think there must be a deeper reason and would want to help. Dumbledore, if still alive in the fanfiction, would likely be more understanding, believing that Harry has a grand plan that he's not aware of yet.
Naruto would probably be extremely happy and excited. He has always been close to Sakura, and seeing her become a mother would be a big moment for him. He might be there to support her during the birth, bringing some of his positive energy to the situation.
In the fanfic world, Ron's reaction to Harry dating Viktor would be complex. Ron has his own insecurities and a sense of loyalty towards Harry. When he discovers this relationship, he may feel like his friendship with Harry is being threatened. He could also be embarrassed because he might think that the wizarding world would gossip about it. His initial response might be to distance himself from Harry, but as he thought more about it and realized that Harry's happiness was important, he might slowly accept the situation, though it would be a long and bumpy process for him.
Hermione would probably be shocked at first. She is a rational person, and this goes against the normal relationship dynamics she is used to. But then she might try to understand it from a logical perspective, thinking about how their relationship has developed over time. Ron, on the other hand, would likely be more vocal in his disbelief and might even make some jokes about it at first.
The Cullens as a whole would be cautious. They would be worried about the implications of a half - werewolf, half - human (with a connection to vampires) baby. They might offer their help and protection, but also keep a close eye on the situation.