Kakashi would be disappointed. He has trained Sakura and hoped she would grow into a great shinobi with good values. If she turns evil, he would feel like he has failed in some way. He would likely try to talk some sense into her, but if that doesn't work, he would have to take appropriate actions to protect the village from her actions.
His friends would be horrified. Sasuke, for instance, who has known Naruto for a long time, would be shocked at this transformation. He might initially try to reason with Naruto, thinking that there's still some good left in him. But as Naruto's psychopathic behavior continues, Sasuke would be forced to consider him an enemy and take action to stop him if necessary.
Naruto would be extremely enraged. He would vow to rescue Sakura no matter what. He would immediately start gathering his friends and form a rescue team. Sasuke, on the other hand, might initially seem more reserved but would also be determined to get Sakura back. He would use his Sharingan skills to track Madara.
Naruto would be devastated. He and Sakura have a long - standing relationship, and her death would hit him hard. He might go into a rage, seeking revenge on whoever was responsible. Sasuke, too, would be affected. Even though their relationship was complex, Sakura was still an important part of his life. He could become more withdrawn or more determined to change the world that allowed such a thing to happen.
Sakura would be heartbroken. She's always had feelings for Naruto, and seeing him insane would be a huge shock. She'd likely try to use her medical skills to find a cure for whatever is ailing Naruto's mind. She might also try to get help from Tsunade, hoping that the former Hokage's knowledge could save Naruto.
Sasuke would be deeply affected. He would probably feel guilty for not being there to save Naruto. At the same time, he would vow to uphold Naruto's ideals and make the ninja world a better place, as a way to honor his friend's sacrifice.
Sakura would probably be angry at herself for being captured. She's a proud ninja. So she would start looking for weaknesses in Itachi's hold on her. Maybe she would try to engage him in conversation to find out his motives, all the while formulating a plan to break free. She could also try to send out some sort of signal to her comrades if possible.
She would be both curious and empathetic. Curious about how the baby ended up where she found it and empathetic towards the baby's situation. So she would start to form an emotional bond with the baby right away. She might talk to the baby softly, trying to soothe it, and then start making plans on how to best care for it in the long run.
Sakura would be over the moon. She would blush deeply and look at Sasuke with so much love in her eyes. She might be at a loss for words for a moment, but then she would find her voice and tell Sasuke that she has been waiting for this moment her whole life. She would also feel a sense of pride that Sasuke has chosen her, after all they have been through. And she would immediately start thinking about how to share the good news with their friends, especially Naruto, who has been like a brother to her and has also been a part of their journey.
Sakura might be initially frustrated. She's used to Sasuke being in control, so seeing him drunk could be a bit of a shock. But then she'd probably feel a sense of protectiveness and try to sober him up.
Sakura might be completely shocked at first. She might freeze for a moment, not believing what's happening. Then she could start crying tears of joy and say yes immediately.