There's no way to really tell if it's common specifically for someone named Jojo. However, in general, reading fanfiction is a popular activity among fans of many different franchises. The Jojo series has a large and dedicated fan base, so it's likely that there are fans named Jojo who partake in reading fanfiction, but we can't say for sure how common it is without more data.
Perhaps this Jojo is interested in exploring different interpretations and stories within the Jojo universe that fans have come up with. Fanfiction often takes the existing characters, settings, etc. from the original Jojo series and creates new and unique storylines. So, this Jojo might be a big fan of the series and wants to see what other fans have imagined.
Some novels may portray the wheel as a symbol of destiny. Characters' lives are like spokes on the wheel, each following a set path that is part of a greater design.
The short stories can expand the world by delving deeper into the cultures. Maybe there are stories about the unique traditions and beliefs of a particular tribe that we only got a glimpse of in the main series. They also might show how different cultures interacted in the past, which adds more layers to the overall world - building. For example, stories about trade relations between different regions that were not explored much before.
The JoJo manga is mainly in black and white. Colored versions exist but are not the norm. Sometimes, colored illustrations are done for promotional purposes or by fans.
I think it's great. The characters are memorable, the plot is full of twists and turns, and the battles are epic. It's a manga that stands out from the crowd.