One important ghost could be the previous Hokages. They have a lot of knowledge and wisdom about the village and its secrets. Naruto seeing them could be a way for him to get some really valuable advice on how to deal with the current threats to the village, like a new powerful enemy or internal political issues.
It could affect the plot by making Naruto more cautious. Since he can see ghosts, he might be constantly on edge, not knowing if a new ghost is a friendly one or a threat. This could lead to him making different decisions in battles or in his interactions with other characters. He might also try to avoid certain places where there are a lot of ghosts, which could change the course of his adventures.
There could be the ghost of the First Hokage. He might have some important wisdom to pass on to Naruto. Maybe the ghost of a fallen comrade who has some unfinished business or a message for Naruto.
Well, it could make the plot more complex. For example, he might discover secrets that others can't. Maybe he'll find out some hidden pasts of the village or certain characters. Ghosts could lead him to new quests or help him understand some old mysteries better.
One of the most interesting could be the ghost of the First Hokage. He has so much knowledge about the founding of the village and the early days of the ninja world. Naruto could learn a great deal from him, like how to better lead and protect the village.
One possible plot could be that Mirabel discovers her ability to see ghosts after the events of Encanto. The ghosts could be the ancestors of the family who have unfinished business. For example, they might want to pass on a long - forgotten family secret to Mirabel that could help the family in some way.
In some 'izuku can see ghosts fanfiction', Izuku may form an unexpected alliance with a powerful ghost. This ghost could teach him unique skills or knowledge that he can use to become a better hero. It could be a story of mutual growth and understanding between the living and the dead.
It could be the ghosts of the First Hokage and his comrades. They might have some unfinished business in the ninja world and see Naruto as the key to fulfilling it. So they raise him to be a great ninja with their ancient wisdom.
It might change his relationships. He could communicate with the ghosts of fallen comrades or enemies. This would give him a unique perspective. Maybe he could understand the motives of former villains better and find ways to prevent future conflicts. Also, it could make his bonds with his living friends even stronger as he shares what he learns from the ghosts.
The Black and White Impermanence didn't really exist. They were just a pair of gods in Han folk culture, characters in myths and legends. Therefore, no one could see the Black and White Ghosts because they only existed in legends.