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.
Jimmy Olsen comics often have exciting adventures and storylines. They usually showcase his interactions with other superheroes and his own heroic deeds.
Superman Legacy is an origin story. It sets the stage for Superman's adventures by showing his roots, his powers emerging, and the challenges he faces as he starts his heroic path.
Superman Legacy doesn't have a one-to-one basis on a particular comic. It takes elements and themes from the broader Superman comic universe to create a fresh narrative.
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.