They could also provide him with advice. Since they were smart witches and wizards, they might have knowledge and wisdom to pass on. Maybe they could guide Harry on how to deal with Voldemort or how to navigate the complex world of Hogwarts politics through the portraits.
The portraits could be a link to his family history. Harry has always been curious about his parents. Having their portraits could allow him to learn more about their lives, their friends, and the things they cared about. This knowledge could in turn help him better understand his own identity and his place in the wizarding world.
The portraits could offer him emotional support. Just seeing his parents' faces might give Harry the strength to face difficulties. For example, when he's feeling down or facing a tough decision, looking at the portraits could be like getting a warm hug from his parents, even if they're not physically there.
He would probably be overjoyed. Harry has always longed for a connection with his parents. Getting their portraits would be like getting a part of them back. He might just stand there, staring at the portraits with a big smile on his face, unable to take his eyes off them.
It could have a huge impact. Maybe it gives him a stronger connection to his past and helps him deal with his insecurities.
The portraits can act as a source of emotional support. Just seeing their faces and the expressions of love and pride on them can boost Harry's confidence. For example, when he's feeling down about his latest encounter with Voldemort, a glance at their portraits might give him the strength to keep going.
In this fanfic, perhaps Harry stumbles upon the portraits while exploring a hidden part of Hogwarts. He might have an emotional moment as he sees his parents for the first time in this way, and the portraits could start interacting with him, sharing long - lost memories and advice.
One interesting story could be that the portraits of Harry's parents start to interact with other portraits in Hogwarts in a very unusual way. They might form a sort of 'portrait alliance' to protect Harry even from within the frames. For example, they could pass on secret messages to Dumbledore's portrait which then gets relayed to the living world.
Obviously, Harry's parents, James and Lily, would be main characters as their portraits are central to the story. Dumbledore could also be an important character. He might be the one who either hid the portraits or knew where they were all along and guides Harry to them.
Hermione and Ron are usually quite common. Since they are Harry's best friends, they would be involved in the story when Harry's parents return. They might be curious about his parents, and also help Harry and his parents adjust to the current situation.
These fanfictions usually change the story of Harry's parents in multiple ways. Firstly, their safety. They might not have had to go into hiding if the wrong boy was believed to be the chosen one. Their relationship with the wizarding community would be altered too. They might not have had the same level of support or the same amount of enemies. Also, the way they are remembered would be different. Their story might not be one of great sacrifice but rather of a normal wizarding family caught up in a misidentified prophecy.
The Weasleys could be likely adoptive parents. They already have a big family and a warm, loving home. They understand the importance of family and would surely welcome Harry with open arms. They could give Harry the sense of a proper family that he has always longed for.
Well, it could lead to all sorts of drama and revelations. Maybe it's a scolding for something he did or a message of love and concern.