So yeah. They're probably not all Geonosians, but they could be. "our" and "we" is either referring to the Geonosians or Separatists. If it were referring to the Seperatists, it does make sense. But I think it's entirely possible that they bagged themselves a couple of scientists, architects, and those with no real political affiliation and said "design this". The Geonosians didn't seem too bright to me, and the Seperatists didn't exactly look like a team of scientists IMO.