Honestly, a lot of the ideas for the character are adapted from the Tokusatsu genre. Specifically, Kaiketsu Zubat and Kamen Rider, two of Shotaro Ishinomori's seminal works. Ichigo is a name I came up with because it literally means "#1." Makes me wonder what you're talking about though. Dragonball's never really overt in the "this is Japan" aspect, and even then, guns are used throughout the series. Launch, Metalitron, South Kai, Hercule, and Mercenary Tao all packed heat. Even going as far back as episode one of Dragon Ball Z, a random farmer pulls a shotgun on Raditz.

As for the lack of Red Ribbon Army, I thought that "non-canon characters" didn't extend to removing characters and organizations sort of vital to the history and feel of the setting. I mean, if there's no Kami, how are there Dragonballs? If there's no Porunga or Shenron, aren't the Dragonballs just fancy glass spheres? If there's no Vegeta line (Planet, King, or PTO Soldier), how do the saiyans become a spacefaring culture? If there's no Frieza, why are there Saiyans on Earth, since their home planet is intact? I mean, without SOME canon characters or organizations, doesn't it defeat the point of a Dragon Ball game entirely?