For a good character interaction between Garou and Saitama, start with their fundamental differences. Saitama is a hero who is bored with the lack of challenge, while Garou hates heroes. Have them start with a fight, but make it a comical one where Saitama's nonchalance annoys Garou to no end. This can lead to some great dialogue exchanges where Garou tries to taunt Saitama into taking him seriously, but Saitama just doesn't care.
Yes, there might be. The Naruto and One - Punch Man fandoms are both large, and it's not uncommon for fans to create crossover fanfics. In such a fanfic, Naruto could be depicted as a fan of Garou for various reasons, like being impressed by his fighting style.
One idea could be a story where Garou and Metal Bat are forced to team up against a common enemy stronger than they've ever faced. They start off hating each other but gradually learn to respect each other's fighting styles.
They contribute in several ways. Firstly, they keep the fans engaged between movie releases. They also introduce new concepts and ideas that might later be incorporated into the movies. For instance, some new villains or plot twists can first be tested in the graphic novels. Also, they can provide different interpretations of the characters, adding more dimensions to the overall MCU franchise. Moreover, they can attract new fans who are more into reading graphic novels rather than just watching movies.
Not always. While the MCU draws inspiration from the comics, there are often changes and adaptations made to fit the cinematic universe and modern audiences.