Since it's a fanfic where Harry sets off his plan, it might involve him planning something related to his friends. For example, he could be devising a strategy to help Ron overcome his insecurities or to protect Hermione from a new threat in Hogwarts. It could also be a plan to change the way magic is taught or perceived in the wizarding community.
Obviously, Harry would be one of the main characters since it's his plan that is being set off. Hermione and Ron would most likely be involved too as they are his closest friends and often accompany him in his adventures. There might also be other characters like Dumbledore, if the plan has something to do with Hogwarts or the fight against dark magic, or perhaps some new characters created specifically for this fanfic.
In the fanfic, Percy might show off his powers in a competition among demigods. He would display his combat skills along with his unique powers, like being able to communicate with sea creatures to gain an edge in the contest.
In the 'harry tells cho chang off fanfic', it could be that Cho Chang has been too clingy or possessive. Harry, who values his freedom and friendships, decides to tell her off. He might say that he needs space to focus on more important things like fighting against Voldemort and protecting Hogwarts. And he could also mention that her behavior is affecting his ability to do what he needs to do.
Well, perhaps Harry uses his ice magic to create amazing sculptures in the Hogwarts courtyard. This would surely draw the attention of his friends and foes alike.
Well, without reading the specific fanfic, it's hard to say exactly. But generally in Harry Potter fanfics, Lily could have all sorts of plans. It might be related to protecting Harry, or perhaps something to do with the wizarding world's future. Maybe she has a plan to deal with Voldemort in a different way than in the original story.
Well, it could involve the Marauders getting into some wild adventures at Hogwarts. Maybe they plan a big prank on Snape that goes awry in a really funny way.
One possibility could be that the Marauders plan to prank the Slytherins in a big way. They might use their Animagus forms to sneak into the Slytherin common room and create chaos, like turning all their robes pink or making their beds float. It would be a classic Marauders' style of mischief.
One possible reason could be to protect himself from the pain and loss he has endured. After all he's been through, like the death of his parents, Sirius, and so many others, turning off his emotions might seem like a way to avoid further hurt.
Perhaps it's a story set in a fictional world. Harry and Lemon could have special powers. They use their powers to help their community or to solve a mystery that has been plaguing their town. They might start as normal siblings but through their experiences, they grow and become more confident in themselves and their abilities.
Maybe Harry hides his intelligence to avoid unwanted attention at Hogwarts. He could be tired of being singled out or feared because of his smartness.