It might be Iruka - sensei. Iruka was one of the first people to recognize Naruto for who he was and give him a sense of belonging. If Iruka were to die, Naruto would remember all those early days of support and kindness. His death would break Naruto's heart as it would be like losing a part of his family, the family that accepted him when no one else did.
One possible plot could be that Naruto witnesses the death of a fellow ninja from his village during a battle. Maybe it's someone he has trained with or has a friendly rivalry. This would cause him to cry as he feels a deep sense of loss for his comrade and also blames himself for not being able to protect them.
It could be a random civilian. This would show Naruto the impact of the ninja world's violence on ordinary people, making him more determined to protect the innocent.
This event can be a huge turning point for Naruto. It might make him more determined to protect others. He could become more serious about his training and his goal of bringing peace to the ninja world. Seeing the death might also make him more empathetic towards those who have lost loved ones.
The aftermath could be Minato's quest for revenge if Naruto's death was caused by someone. He would use his skills and knowledge to track down those responsible. Or, he could be plunged into a deep depression. He might isolate himself from the other spirits or entities in the afterlife. His whole existence could become centered around his grief and his memories of Naruto.
Minato would likely be devastated. He sacrificed his life for Naruto, hoping for a great future for his son. Seeing Naruto die would shatter his hopes and dreams. He might first be in denial, unable to believe what he's seeing. Then, his grief could turn to anger, either at the situation or at those he believes are responsible. It's a tragic scenario that would change Minato's afterlife perception and his sense of purpose, which was always tied to Naruto's well - being.
In fanfiction, Jiraiya seeing Naruto as Hokage can be a very emotional moment. It could be a vision Jiraiya has in a story where he's still alive, or perhaps it's a memory in a story set after his death. This often shows Jiraiya's pride in Naruto and his belief in Naruto's potential to lead the village.
It might be an old enemy of Naruto who has come back for revenge. For example, someone from the Akatsuki who wasn't completely defeated before. They could target Naruto again and put him in a life - threatening situation, which makes Kurama cry.
He might be amazed. Naruto is used to his own world and seeing a fan - made interpretation like an AMV fanfiction would be like seeing a new side of his story.
You can try some well - known fanfiction websites like FanFiction.net or Archive of Our Own (AO3). These platforms usually have a large collection of Naruto - related fanfictions, and you might be able to find 'sakura cries for naruto fanfiction' among them.