DB Heroes doesn't follow the manga exactly. It takes inspiration and builds on it, making changes to suit the specific requirements of the series. However, the core elements are still recognizable.
It could be a fan - made story that combines elements from Naruto and Dragon Ball (db). Maybe it features Naruto characters in a Dragon Ball - like setting, or vice versa.
The majority of manga are not in color. It's a common practice in the manga industry to use black and white for regular publications. But for certain limited series or special projects, color might be employed to make them stand out.
The JoJo manga is mainly presented in black and white. However, there might be some special editions or colored illustrations for promotional purposes, but the standard version is not in color.
Well, most likely Naruto would be one of the main characters. And from Dragon Ball, it could be Goku or Vegeta. They are the most popular characters in Dragon Ball, so in a 'naruto db super fanfic', the author might choose them to interact with Naruto in interesting ways, like having Naruto train with Goku to become stronger or Vegeta challenging Naruto to a friendly sparring match.