It could also be that the Potters are under some sort of magical influence or curse. In the fan fiction world, there could be a dark force at play that makes them see the twins as more important. This force might be manipulating their emotions and perception, leading to the neglect of Harry.
Harry might become withdrawn and introverted. Feeling unloved and unwanted, he could start to keep to himself more, spending time alone in his room or exploring the grounds of their home alone, trying to make sense of why his parents seem to favor the twins.
One possible motive could be that the Potters discovered some dark plot by the Malfoys involving Harry. Maybe they found out that the Malfoys were planning to indoctrinate Harry into their pure - blood supremacist ideology against his will. So, to protect Harry from that, they kidnapped him.
I'm not sure if the Potters (as in the characters in the Harry Potter series) would give away Harry Potter fanfic. In the official lore, there's no indication of them doing so. Fanfic is more of a creation by fans in the real world rather than something the fictional characters would be involved with.
There's no real reason for the Potters to give away fanfic. Fanfic is a fan - created content, and the Potters are fictional characters. They don't exist in the real world where fanfic is created and shared.
It could slow down the plot. For instance, if Harry's glasses are constantly malfunctioning, he might miss important clues or signals. This would add more obstacles to his journey of solving mysteries or fighting against the dark forces.
One interesting story could be about the Potter family's daily life before Harry goes to Hogwarts. Maybe how James and Lily Potter raised Harry in his early years, their family traditions, and the magic they used around the house.
Obviously, Harry Potter himself is a main character. He's at the center of many of these fanfictions, whether it's about his growth within the family or his relationships with other family members.
One possible plot twist could be that Snape discovers some hidden magic in Harry that he didn't expect. Maybe a power that's related to the Potters but also has a connection to Snape's own family. Another twist could be that the other Potter family members don't approve of Snape adopting Harry, leading to a family feud within the wizarding world. And perhaps, there could be a dark force that tries to use Snape's new relationship with Harry against them.
Well, it could be really interesting. Snape might struggle with his feelings for Harry, given his past with James Potter. He'd have to balance his old grudges and his new role as a father figure. Harry would likely be confused at first, but also maybe a bit relieved to have someone, even Snape, looking out for him. And the wizarding world would be in for a shock to see Snape in such a different role.