In most comic storylines, Jimmy Olsen isn't a guardian. He's more often involved in reporting and assisting Superman rather than having a guardian role.
I'm pretty sure it's not real. There's no concrete evidence or reliable source to confirm its authenticity. It could just be a story someone came up with for entertainment.
One plot idea could be that after the body swap, the female Jimmy Olsen has to navigate the male - dominated world of reporting in a different way. Maybe she uses her new male body to break into areas that were previously off - limits to her as a female. Another could be that she has to deal with the relationships in Jimmy Olsen's life, like his friendships and professional contacts, while in his body. And perhaps there are some comical misunderstandings when she behaves in ways that are different from what people expect from Jimmy Olsen.
Her character would likely experience a shift in how she is perceived by others. In a male body, people might take her more seriously at first glance. This could give her new opportunities to prove herself in the journalistic world. However, she may also face new challenges like having to deal with male - specific insecurities or expectations. Emotionally, she might have to suppress some of her more 'feminine' emotional responses in order to fit into the role of Jimmy Olsen, which could be both a struggle and a source of character growth.
Jimmy in 'Jimmy's Confessions' could be a character with a complex personality. He might be a middle - aged man who has led an eventful life. Maybe he's a writer who is using his confessions as a way to tell his own story, or he could be someone who has just reached a point in his life where he feels the need to unburden himself of all his secrets.
One possible fanfiction could be that Jimmy has a secret mission, and Heloise accidentally gets involved. They start off not getting along well because of their different personalities. But as they face difficulties during the mission, they gradually learn to understand and rely on each other, and in the end, they become great friends.
I'm not sure who specifically 'Matt Olsen' is in the context of science fiction. There could be many people with this name. Maybe he is an author, an actor in science - fiction works, or someone involved in the production side like a director or a screenwriter. Without more context, it's hard to be definite.