Well, Boruto might have a range of reactions. If the fanfiction shows Naruto as a really powerful and cool hero, which he is, Boruto would probably feel proud. But if it's something that twists Naruto's character in a negative way, he would likely be angry or defensive. He respects his father a great deal, so any false portrayal could upset him. He may also find some of the more out - there or creative fanfictions amusing, like ones that put Naruto in a completely fictional adventure that's way different from what actually happened.
Sasuke often appears in different story arcs of the Boruto manga, depending on the current plot and mission. Sometimes he's on a solo mission, sometimes he's involved in events related to the village.
In fanfiction, Sasuke's realization of Sakura's pregnancy can be filled with drama. He might question his own ability to be a father. However, his love for Sakura would drive him to overcome his doubts. He could start learning about pregnancy and child - rearing, and his relationship with Sakura would become more affectionate and caring as they anticipate the arrival of their baby.
Boruto's character development could be a complex journey. At first, he may feel overshadowed by his parents' fame and power. This could lead to him acting out or trying to prove himself in the wrong ways. However, as he experiences more of the ninja world and faces challenges, he starts to understand the true meaning of his parents' actions. He might develop a more empathetic side, seeing things from the perspective of others, especially those affected by Naruto and Sasuke's past actions. He also grows in terms of his combat skills, learning from both his father's brute force and Sasuke's finesse. His character arc could be about finding his own identity within the context of his parents' great reputations.
Naruto is likely to be popular too. Even though it's a Boruto x Sasuke fanfic, Naruto's relationship with both of them is so important. He could play a role in supporting them from the sidelines or even getting involved in a crucial part of the story.