Sasuke would probably be very confused at first. He has spent so much time hating Itachi for what he did to the Uchiha clan. Seeing Naruto befriend Itachi would make him question his own long - held beliefs. He might initially be angry with Naruto for seemingly siding with his enemy.
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's reaction could be complex. At first, he would be enraged. After all, the Rinnegan is a symbol of his power and his journey to gain strength. However, he might also have some mixed feelings. He and Naruto have a deep bond, and he might wonder if Naruto had a good reason for taking it. But overall, his initial reaction would likely be one of fury and a desire to get his power back.
There could also be friends who are so loyal to Naruto that they would consider following his request if they truly believe it's for the greater good. However, they would be deeply pained by it. Kakashi, for instance, might understand Naruto's selfless nature but would also struggle with the moral and emotional implications of taking his life.
Sakura would probably be a bit shocked at first but then be very supportive. She has always cared about both Naruto and Sasuke, so she would likely be there to help with the baby's medical needs if any. Kakashi would be the cool uncle type. He'd offer his wisdom and maybe some training tips for when the baby grows up.
His friends from Team 7, like Kakashi, would feel responsible for Naruto's situation. Kakashi would likely use his resources to find a proper shelter for Naruto. Shikamaru and the others might come together to form a sort of support group for Naruto. They would pool their resources, like money and food, and also try to cheer him up by sharing stories and jokes.
The fanfic could be centered around Sasuke's best friends, Naruto and Sakura, and how they interact with Sasuke's Sharingan. For instance, Naruto might be curious about the Sharingan's abilities and constantly ask Sasuke to show him new tricks. Sakura, being a medical ninja, could study the Sharingan's effects on Sasuke's body to ensure he doesn't overuse it and harm himself.
In a fanfic like this, Sasuke's Sharingan could be the key to unlocking a hidden power within his best friends. Maybe his Sharingan has a special connection to Naruto's Nine - Tails chakra. As they fight side by side, Sasuke uses his Sharingan to guide Naruto in controlling the Nine - Tails better. Sakura, on the other hand, could learn new medical jutsu inspired by the insights from Sasuke's Sharingan, deepening their bond as they all grow stronger together.
At first, Naruto would be in disbelief. He has always trusted his friends wholeheartedly, so this would be a huge blow. He might then feel a deep sense of anger and sadness. However, Naruto being Naruto, he would likely also start to look for ways to prove his innocence or the misunderstanding. He might go on a journey of self - discovery to figure out what went wrong and how he can win back his friends' trust, all while dealing with the pain of the betrayal.