The Akatsuki members themselves would have mixed reactions. Some, like Itachi (if he were still alive in the fanfic), might see Naruto as a potential asset but also a threat to their long - term goals. Kisame might be amused by Naruto's presence and see him as a new source of entertainment. Meanwhile, the Leaf Village elders would be outraged. They would see Naruto as a traitor and start devising plans to either bring him back or eliminate him.
Naruto would probably be initially cautious but also curious. He has a knack for seeing the good in people, so he might try to befriend the Akatsuki sister. Kurenai, on the other hand, would be more guarded. She is a more experienced ninja and would be wary of any Akatsuki member. But she also might see an opportunity to gain intel from the sister.
Sasuke would likely be initially shocked. He's a man who has been through a lot and is used to a life of solitude and danger. But then, a sense of protectiveness would kick in. He'd become more vigilant about the safety of Sakura and their unborn child. He might also start to think about how to be a better father than his own was, in some ways, trying to break the cycle of his family's past.
They might be overjoyed. Since Sarada is part of their family, they would likely welcome her with open arms and big smiles. They could be very proud of how far she has come in her ninja training.
Some members might be skeptical at first. For instance, Kakuzu would be worried about how her presence could affect their money - making operations. But others like Itachi might see her as an opportunity to change the Akatsuki from within. He might try to guide her and use her positive energy to sway the group towards a more noble path.
The Hidden Leaf villagers would be shocked. They see Akatsuki as the enemy, so they would think Naruto and Sasuke have betrayed them. Kakashi would probably be very concerned and try to find out their reasons. Sakura would be heartbroken and might even try to go after them to bring them back. As for the Akatsuki members themselves, some might be suspicious of Naruto and Sasuke's motives at first, while others might see it as an opportunity to use their power for Akatsuki's goals.
Naruto would probably be very confused at first. He's always seen the Akatsuki as the enemy, so being taken there by Fem Itachi would be quite a shock. He might be on guard and constantly looking for a way to escape.
Naruto would be devastated. He has always considered Sakura as a dear friend and teammate. He would probably try to convince her to come back at first. If that fails, he might see it as his mission to bring her back by force if necessary, believing that she has been led astray. Sasuke, on the other hand, might have a more complex reaction. He has his own issues with Konoha, so he might understand Sakura's desire to leave on some level, but he would also be suspicious of her motives for joining Akatsuki.
Well, initially his friends in Konoha would be horrified. Naruto has always been a symbol of hope for Konoha. But if he became the Akatsuki leader in a fanfiction, they would start to question everything. However, as time passes, they might start to see the positive changes Naruto is trying to bring to the Akatsuki. For instance, if Naruto is using his godlike powers to stop the Akatsuki from their more evil plans and instead make them a force for good, his friends might gradually come around. But it would be a long and difficult process, filled with a lot of mistrust and misunderstandings at first.