Sakura might initially be very angry. She has her own strength and pride, and being kidnapped by Sasuke, someone she once cared for deeply, would be a huge blow to her self - esteem. She could try to fight back immediately, using her medical ninjutsu skills and combat training to attempt an escape.
Kakashi would be more reserved but still show his support. He might give Sasuke some advice on being a father based on his own experiences with his team. Shikamaru would be practical, thinking about how the baby will affect the village's future and offering some logical solutions to any potential problems that might come up.
Sakura might be heartbroken. She's been in love with Sasuke for so long. She could initially go into denial, thinking it's just a temporary thing. Then she might get angry and vow to prove herself to Sasuke, perhaps by becoming an even stronger ninja.
Well, Naruto might be furious. He's always been protective of Sakura. He'd probably drop everything he's doing and go after Sasuke to rescue Sakura. Naruto has a strong sense of justice and loyalty, especially towards his friends. And Sakura is one of his closest friends, so he won't stand by and let her be in danger.
She could be heartbroken. Sakura has always loved Sasuke deeply, so his leaving for Naruto would be a huge blow to her. She might initially be in denial, not believing that Sasuke would choose Naruto over her.
Fans have a wide range of reactions. There are those who are vehemently against it. They have a strong emotional investment in the Sasuke - Sakura relationship from the original series. Then there are others who are more open - minded. They see it as an interesting exploration of different relationship scenarios within the fanfiction world. These fans might engage in discussions about why the author chose to take such a route and what it means for the characters' development in the fanfic.
Some in the ninja world would likely be shocked at first. The idea of Naruto and Sasuke having a son together goes against the traditional views of many. But those who are close to them, like their friends from Team 7, would probably be supportive. Kakashi, for example, might see it as a new step in the evolution of the ninja world's relationships. However, there would also be those who oppose it, especially from more conservative clans who might fear the implications of such an unorthodox union on their power structures.
Sakura would probably be very hurt. She has deep feelings for Sasuke, and if she found out it was just a ploy to escape, she'd be heartbroken. She might also be angry at being used in such a way.
She could try to talk Sasuke down. Sakura is a strong - willed character. She might start by asking Sasuke what's wrong, trying to reason with him, and reminding him of their past relationship, in an attempt to defuse the situation.
At first, Naruto is probably shocked and confused. He might not understand why the village would take such a harsh step just for hurting Sasuke. He may feel betrayed, especially if he thought he had friends and allies in the village.