Peeves is a poltergeist in the Harry Potter series. His origin isn't fully detailed in the books. However, it's known that he has been at Hogwarts for a very long time, causing mischief long before the main characters arrived. He seems to be a part of the magical fabric of the school, popping up here and there to play pranks on students and staff alike.
Yes, there are quite a few. You can find them on fanfiction websites like FanFiction.net or Archive of Our Own. Some explore really interesting scenarios where Harry befriends Peeves and they get into all sorts of magical mischief together.
One common theme is the clash of personalities. Hermione is studious and rule - abiding while Peeves is mischievous. Another theme is the idea of Hermione trying to reform Peeves. And often there's the theme of unexpected friendship that might develop between them.
One common theme is the idea of an outsider friendship. Both Harry and Peeves are a bit of outsiders in different ways. Harry is the Boy Who Lived and has a lot of expectations on him, while Peeves is a poltergeist not fully accepted by the Hogwarts community.
The Enfield poltergeist is indeed a real - life case. It happened in the late 1970s. The Hodgson family, who lived in Enfield, reported all kinds of spooky stuff. Doors slammed shut by themselves, voices were heard that didn't seem to come from anyone in the house. Some people think it was a hoax, but others believe there was something truly paranormal going on. There were even some pictures and recordings made during the time of the events, which added to the mystery.
No, it isn't. Poltergeist is purely a creation of the filmmakers' imagination. It's designed to scare and entertain rather than being rooted in reality.