There would be a great deal of love. Hinata's love for Naruto would be palpable throughout the funeral. His friends' love too. They would all be mourning not just the loss of a great ninja, but also a beloved friend. Anger could also be a part of it, especially if his death was due to some foul play. Sasuke might be filled with rage at the thought of someone harming Naruto.
Love is a very common emotion. It could be romantic love between two crew members from different species or a deep platonic love among friends. Fear is also frequently shown, especially when characters encounter new and dangerous alien species or face the unknown in space exploration. Another common emotion is determination. The characters in Star Trek fanfiction often show great determination to achieve their goals, whether it's saving a planet or solving a scientific mystery.
In fanfiction, Naruto might be a brave and energetic wolf, always leading the pack into adventures, much like he does with his friends in the original story. Sasuke could be a lone wolf, brooding and mysterious, with his own hidden motives. Sakura might be a nurturing wolf, taking care of the injured in the pack.
Surprise. He would be amazed at how much he has changed over time.
He'd probably be a bit of shocked. Since fanfiction often contains things that are quite different from what he knows. For example, if it shows a different future for his friends, it would be unexpected for him.
Love is very common. It can be a romantic love between the main characters. Another one is sadness, often used when there are tragedies like the loss of a loved one. Anger also appears when characters face injustice or betrayal.
The Naruto - Kid Buu fusion in fanfiction could be depicted as a being with a unique fashion sense. Since Naruto often wears orange and Kid Buu is mostly pink, the fused form might have a combination of those colors in its clothing or body markings. In terms of abilities, it could be shown as having the speed of Naruto when he uses his chakra to enhance his movement, combined with Kid Buu's ability to transform parts of his body into weapons. For example, the fused form could create Rasengan - like attacks from its hands which are also able to stretch like Kid Buu's arms.
Their relationship could be one of rivalry. The brother might feel overshadowed by Hagoromo and see Naruto as a way to prove himself. So, he initially tries to use Naruto against Hagoromo's ideals but later realizes the error of his ways and becomes an ally to Naruto.
It usually shows the unconditional care and sacrifice a mother makes for her children. The emotions can range from tender to intense.
Well, in some fanfics, Naruto might have Starkiller's powers or similar fighting styles. Maybe he uses force abilities or has a lightsaber-like weapon.
Some fanfictions might show Naruto as evil due to a traumatic event that warps his personality.