Surprisingly, Sasuke could end up being a support for Naruto in this situation. They have a complex relationship, but both have known what it's like to be alone and ostracized in Konoha in different ways. Sasuke may understand Naruto's pain and they could end up working together to face the world that has been cruel to them both.
Jiraiya could be one to support Naruto. Jiraiya has a connection with Naruto already, and he's the type who goes against the norm. He would likely take Naruto under his wing and help him grow in strength and confidence away from Konoha.
Sakura might try to stop Naruto. She is one of his closest friends. She cares about him deeply and would be worried about his safety. Also, she would understand that running away is not the best solution to whatever problems he is facing.
Sasuke could be one of the characters to support Naruto. They have a deep bond, and Sasuke might understand Naruto's reasons for wanting to change Konoha. Also, Shikamaru, being a smart strategist, might see the potential in Naruto's plan and choose to support him.
Sasuke could be one of the characters to support Naruto. Given their complex relationship and Sasuke's own issues with Konoha in the past, he might see Naruto's cause as just. Another one could be Jiraiya. If he were alive and found out about the real reasons behind Naruto's revenge, he might side with Naruto as he always cared for him deeply. Also, some of the outcast ninja within Konoha, like those who have been discriminated against because of their bloodline or lack of skills, might support Naruto as they also have grudges against the village system.
Maybe some of the more conservative village elders. They have always been a bit wary of Naruto because of the Nine - Tails inside him. So they might be behind his capture in the fanfiction.
Shikamaru might be sent to find Naruto. He's known for his intelligence and strategic thinking. The village elders might trust him to be able to track Naruto down and either convince him to come back or at least find out his intentions. Shikamaru also has a certain respect for Naruto and would understand his motives to some extent.
His mentor, Kakashi, would also be there to help. Kakashi is very protective of Naruto. He would use his experience and calm demeanor to make sure Naruto gets the best possible care and support during this crisis.
It's possible that the child is an orphan Naruto found. Naruto, having known the pain of being alone as a child, decides to take the orphan under his wing. He brings the child back to Konoha to give it a home and a family within the village.
The combined forces of the remaining ninja clans in Konoha could also pose a threat to evil Naruto. If they put aside their differences and work together, they could pool their resources, jutsu, and manpower to try and halt Naruto's rampage. Although Naruto is extremely powerful, the collective strength of the village's ninja clans could potentially be enough to subdue him.
Perhaps the Konoha leadership made a bad decision. They might have thought that distancing themselves from Naruto would be better for the village's overall image. Or they were influenced by some elders who held grudges against Naruto's father and took it out on Naruto.
Sakura could be one of the main characters. She has a long - standing relationship with Naruto and might play a role in convincing him to return. Maybe she tells him about the state of the village's hospital or how his friends miss him.