There are many possible characters. Harry's friends, like Ron and Hermione, would be involved as they react to this new Harry. The house elves might also be part of the story, as the founders had different views on house elves. For example, if Harry was influenced by Helga Hufflepuff, he might have a closer relationship with the house elves and try to improve their situation. And there could be other magical creatures that the founders had a connection with, such as the centaurs or the giants, which could come into play in the story.
Obviously, Harry Potter himself. Then there would be the four founders: Godric Gryffindor, Salazar Slytherin, Rowena Ravenclaw, and Helga Hufflepuff. They could be present in some form, either as ghosts or through memories guiding Harry. Dumbledore might also still play a role, perhaps as a sort of mediator between the modern world and the founders' teachings that Harry is receiving.
Well, in this type of fanfiction, Harry's parents, James and Lily, could still be important. Their memories or the things they left behind could interact with the founders' influence on Harry. And of course, the villains like Voldemort would be there. Harry's upbringing by the founders would give him a different approach to fighting Voldemort. Additionally, the Hogwarts professors would be involved, as they would notice the very different Harry who has been raised with the founders' ways.
The best chapter pointer here is Chapter 11, "She Smiled, He Panicked". It opens with After a meeting, Shang Shaojing pinched the bridge of his nose, tired, and... and closes on Miss Qin, please accompany us to the police station to explain this....
The best chapter pointer here is Chapter 51, "The Great Lodging Competition". It opens with Oh, okay." After uttering two syllables indifferently, Jiang Li bent down... and closes on If I opened a bar here, wouldn't I become a savior?" Jiang Yan was....
Chapter 60 is the strongest chapter-level answer because it starts from What's with Jiang Yan, treating his own sister Jiang Li like this?" "He... and follows through on And in traditional characters?" "What else?.
A practical answer is Chapter 49, because it turns the idea into a concrete scene. The chapter opens with My phone!!!" Jiang Yan's roar echoed continuously through the mountains in..., adds pressure through The guest with the highest score will receive a series of resources from..., and ends on.
The best chapter pointer here is Chapter 15, "The Autistic Teen Jiang Shixu". It opens with Jiang Shixu woke up from those nightmares filled with blood and darkness,... and closes on Since she didn't move, Jiang Shixu also stayed put, and the kitchen, which....
The best chapter pointer here is Chapter 52, "Your Child is in Danger Now". It opens with The village chief and the woman behind him exchanged a glance, "This... and closes on And at this point, they might as well try a desperate remedy for a....
Chapter 59 is the strongest chapter-level answer because it starts from After walking for about two or three hundred meters, the old man stopped... and follows through on My phone, my cigarettes, my champagne, oh how I miss you......" He swore,....
A practical answer is Chapter 59, because it turns the idea into a concrete scene. The chapter opens with After walking for about two or three hundred meters, the old man stopped..., adds pressure through Your brother might just be kind enough to take you in., and ends on My phone, my cigarettes.
A practical answer is Chapter 39, because it turns the idea into a concrete scene. The chapter opens with Qi Tianyu had been looking forward to watching Jiang Li's drama unfold., adds pressure through It's not by some great master, I copied it myself., and ends on His original intention was just.
The best chapter pointer here is Chapter 21, "Uncle Policeman, They Are the Ones Causing Trouble!". It opens with Jiang Li's clear and logical explanation had everyone stunned in place. and closes on But the implications could be different..