I originally concepted them without any female parts, but you can thank my cousin convincing me to change that back in high school.
The Zuroks are the more "human" like creatures I've concepted. Even though I like Star Trek and Mass Effect, I try to stay away from the Star Trek-esque practice of making aliens "humans with green skin" or something. At the same time, I want the audience to connect with the characters. It's an art and a science, and takes special care to not fall into the Uncanny Valley. There's also the difference between Hard Science Fiction vs. Science Fantasy. The characters from the franchises I mentioned definitely fall into the latter.
I checked out of all this stuff when "Heavy Metal" stopped publishing.