One possible theme could be friendship. Even in a 'buff Jimmy' context, the relationship between Jimmy and Cindy might explore different aspects of their friendship, like how they support each other in new and different situations.
In 'Pulp Fiction', Jimmy is that character who has this sort of regular - joe - caught - in - the - middle - of - mayhem feel to him. He's not part of the main criminal underworld like Jules and Vincent in the purest sense, but his connection to them drags him into their wild situations. For example, when they need a place to clean up and hide out for a bit, they turn to Jimmy's place, which causes all kinds of tension and comical - yet - dangerous moments.
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.
Jimmy was a guy whose house was used as a hideout or a place for the characters to deal with certain situations. His presence added an element of complication to the plot.
In my view, Jimmy isn't racist in Pulp Fiction. His character seems more focused on other issues and his interactions don't show any discriminatory tendencies based on race.