Since the details are scarce, Gary could be anyone. He might be an ordinary person living an extraordinary life as a gay man. Maybe he is a local figure in a community known for his contributions, or perhaps he is just a character in a story that is meant to represent certain aspects of the gay experience.
It could be just a random chant or repetition that someone has associated with the movie for no particular reason. Maybe it was part of a joke or a personal mnemonic device to remember something about 'Pulp Fiction'.
In the 'kid a gary carter story', Gary Carter might be a local figure. Maybe he was a shop owner who was always friendly to the kid. Or perhaps he was an old-timer in the neighborhood who had many interesting stories to tell, and the kid was always drawn to him, and that's how their story began.
Harry Potter is likely to be one of the main characters. He and Neville often interact in the original series, and in the fanfic, their relationship could be further developed. Hermione Granger could also be a main character. Her intelligence and knowledge of magic could play a role in whatever adventures or situations Neville gets into. Ron Weasley might be there too, adding his humor and loyalty to the group.
Luna Lovegood could also be an interesting addition. Her unique perspective on magic and the wizarding world might bring new ideas to the group. For instance, she could have insights about some of the more mysterious magical creatures or phenomena that they come across, which could be crucial in their quests or battles.
Some fanfictions make Neville OP by changing his backstory. Maybe he was secretly trained by a powerful wizard in his childhood, and this hidden training surfaces during his time at Hogwarts, allowing him to outperform his peers and take on challenges that would be impossible for the regular Neville. This gives him an edge and makes him an OP character in the fanfiction world.
I don't know who Gary Houseman is in this story as I'm not aware of the 'balls out the gary houseman story'. He could be an ordinary person who got into an unusual situation that led to the creation of this story.
Gary Kulik is probably a veteran. In the 'Gary Kulik War Stories', he is the central figure. He might have had a long and eventful military career, and these stories are a way to document and share his unique experiences, whether they are heroic deeds, or simply the day - to - day survival in the war zone.
Not having read 'Ladies in Black The Gary Thain Story', it's difficult to say precisely who Gary Thain is. But generally, in a story named after someone like this, he is likely to be the central character. He could be a person with his own dreams, fears, and desires. His story might be about his growth, his struggles, and how his interactions with the ladies in black shape his character and his life. Maybe he comes from a particular background that is relevant to the overall theme of the story and his encounters with these women are what make the story unique.