Harry, Ron, and Hermione would be obvious choices as main characters. They already have a lot of experience with magical mysteries and adventures at Hogwarts. Their knowledge of spells and the castle's secrets would be very useful in a ghost hunt. Another option could be the Weasley twins. They are known for their mischievous nature and creativity, which could make for an interesting take on a ghost hunt. They might use their prank - related magic items to track or interact with ghosts in a unique way.
The main characters could be a group of Hufflepuff students. Hufflepuffs are often overlooked in the main Harry Potter story, but they are known for their loyalty and hard work. They could band together to form a ghost - hunting group. Their determination to solve the mystery of the ghosts in Hogwarts could drive the story. Maybe they are joined by a ghost of a former Hufflepuff student who guides them. Another possibility is that Professor McGonagall could be one of the main characters in a way. She could be the one who assigns or oversees the ghost hunt, and her wisdom and magical expertise would play an important role in the story.
I don't know the exact fanfic, but it could be Harry, Hermione, and Ron as they are often central characters in Harry Potter - related stories. They might be leading 'the hunt' for whatever the objective is in the fanfic.
It's also possible that some of the Death Eaters themselves could be main characters in a sense. For example, Bellatrix Lestrange could be a central figure if the fanfiction focuses on the power struggle within the Death Eater ranks during Harry's hunt, or if there is some backstory or different take on her relationship with Voldemort and the other Death Eaters.
I think Luna Lovegood would make an excellent main character in a Harry Potter Ghost Hunters fanfic. She already has a very open - minded view of the magical world and is quite in tune with the more ethereal aspects of it. Fred and George Weasley could also be main characters. Their mischievous nature would lead them to be interested in ghost hunting, and they could use their inventions to help in their investigations. Additionally, Ginny Weasley could be part of the group, being brave and having her own experiences with the supernatural at Hogwarts.
Hermione might also be a main character. She's known for her intelligence and problem - solving skills. In this fanfiction, she could be trying to figure out the mystery behind the 'ghost of you' phenomenon, using her vast knowledge of magic and lore.
The female potter herself would be a main character, of course. She could be a young and determined artist, trying to break free from the traditional role of a potter in her village. There could also be an experienced hunter who initially doubts her abilities but later comes to respect her. Another character could be the village elder who gives her permission to join the hunt, adding an element of authority to the story.
The main characters are obviously Harry and Daphne. Harry, being the Boy Who Lived, has a lot of experience with fighting Voldemort and is determined to destroy all the Horcruxes. Daphne, on the other hand, is likely a Slytherin or has some connection to Slytherin. She brings her own set of skills and knowledge to the Horcrux hunt. Maybe she has a good understanding of dark magic or some family secrets that can be useful.
There is probably a lead investigator. He or she is likely very knowledgeable about the paranormal.
In a 'ghost hunt story', the main characters usually are those who are drawn to the mystery of the supernatural. There are the ghost hunters, who are experienced in dealing with the unknown. They bring their knowledge and tools to the table. Then there are the witnesses, like the people who live near the haunted place or have had strange experiences there. Sometimes, there's also a psychic or medium who claims to be able to communicate with the spirits. These different types of characters interact and their experiences and beliefs collide, which makes for an interesting 'ghost hunt story'.
Percy is a must - have. But also consider characters like Zoe Nightshade, even though she passed away in the original series, she could be brought back in a unique way in the fanfiction. There could also be new characters, like a young huntress who is initially skeptical of Percy but then grows to respect him. And don't forget about Annabeth, who could have a role, maybe she's worried about Percy getting involved with the hunt and her feelings play into the story.
Neville Longbottom could be a main character. He has always had the potential for great things and in a world without Harry, he would be likely to step into the spotlight. He has the courage and the connection to Hogwarts that could make him a central figure in the fight against evil.