Sasuke would be furious. He's always been protective of Naruto in his own way. He would immediately start looking for her, using all his skills and resources. He might even go on a rampage if he thought Naruto was in serious danger.
Sasuke would be extremely worried. He might initially blame himself for not being there to protect Naruto. He would then start gathering information about the kidnapper. His reaction would be very intense as Naruto is one of the most important people in his life. He would track down the kidnapper without hesitation, and when he confronts them, his Sharingan would be blazing with anger. He'd use all his combat skills to defeat the kidnapper and rescue Naruto, and afterwards, their relationship might become even stronger.
Sasuke would first be in shock. But then, his Uchiha pride and his bond with Naruto would kick in. He would set out on a mission to rescue her. He'd be very focused and determined. Along the way, he might have to face some of his own demons as well as the kidnapper. And when he finally finds Naruto, he'd be both relieved and angry at the same time. He'd probably make sure the kidnapper never dares to do such a thing again.
Well, one possibility could be that Sasuke's overzealous fan wants to use female Naruto as a way to get Sasuke's attention. Maybe the fan thinks that by having Naruto in their control, they can manipulate Sasuke into coming to them. Another plot could be that the fan has some sort of grudge against Naruto for being so close to Sasuke and decides to kidnap her out of jealousy. It could also be that the fan has a warped sense of love for Sasuke and believes that by getting rid of Naruto, Sasuke will finally notice them.
In some cases, Sasuke could be angry. He might see Naruto's request as a sign of weakness or as Naruto giving up too easily. He could lash out at Naruto, telling him to fight instead of asking for death. However, he would still be deeply troubled by the request and would probably struggle with it for a long time, constantly thinking about whether or not he should consider it.
Sakura's reaction would be complex. She has deep - seated feelings for Sasuke, so it would be a hard pill to swallow. However, as a medical ninja, she would also feel a sense of responsibility towards Sasuke's pregnancy. She might offer to be Sasuke's doctor throughout the pregnancy. Naruto's friends like Rock Lee would be over the moon for him. Lee would see it as Naruto achieving another great milestone in his life. He would constantly cheer them on and might even start training extra hard in case he needs to protect the new family. As for the other Konoha ninjas, they would initially be skeptical but gradually accept the situation as they see Naruto and Sasuke's determination to build a family together.
Sasuke would probably be very guarded at first. He's not used to dealing with something so innocent and vulnerable. He might be suspicious of the baby's presence and think it's some sort of trap.
Sakura would be devastated. She has deep feelings for both Naruto and Sasuke. She might turn against Sasuke completely and try to take revenge herself. Kakashi would be in shock. He has mentored both and would likely feel like he failed in some way. As for the other ninja from the Hidden Leaf, they would be angry and mournful at the loss of their hero Naruto.
The Uzumaki family might be a bit shocked at first. But Naruto's kind - hearted nature could make them eventually come around. His mother Kushina might be more accepting as she always wanted Naruto to be happy. As for Sasuke's family, well, it's a bit more complicated. Since Sasuke is the last of the Uchiha, his family's traditional values might be a hurdle. However, if Sasuke is determined, he might be able to convince any remaining family members or those who care about the Uchiha legacy that his relationship with Naruto is a positive thing.
Naruto would probably be very confused at first. He trusts Sasuke, even if it's a Fem Sasuke in this fanfiction, and he wouldn't expect to be kidnapped by her. So, his initial reaction might be to try and talk to her, asking her why she's doing this.
Sasuke might be initially surprised. He is used to the Sakura from his past, so seeing a different, more mature future Sakura could catch him off guard.
I think young Sasuke would have a very intense reaction. He was so consumed by his hatred for Itachi at that young age. A Sasuke vs Itachi fanfiction would be like a trigger for him. He would be eager to see how the fictional fight is portrayed. If Sasuke in the fanfiction is shown as strong, it might fuel his own ego and make him strive even harder to become powerful. However, if the fanfiction shows Itachi as superior, it could enrage him. He might feel that it undermines his own goal of defeating Itachi and he might even want to find the writer to correct their 'wrong' view.
Sasuke could be intrigued. If he comes across a well - written fanfic that really captures the essence of his relationship with Naruto or offers a new perspective on his goals and journey, he might get drawn into it. He might start to think about how these different ideas could fit into his own understanding of his life and the world around him. For instance, if a fanfic shows him a different path he could have taken, it might make him reflect on his choices.