Half-Life's scientists might look like endless clones thanks to memory limitations of the time, but that hasn't stopped them from taking on personalities of their own. 'scientist01' became Isaac Kleiner in the sequel, but in the '90s, he was dubbed 'Walter' by the community, even spawning fan-fic called "Walter's World". 'scientist02' meanwhile became known as Einstein, thanks to the striking resemblance, but concept and 3D artist Chuck Jones, who designed Gordon Freeman, says he was actually inspired by President George Washington.
I emailed Chuck Jones to ask about a fan theory that 'scientist04' is based on Oppenheimer (something lead writer Marc Laidlaw said was unlikely when asked by TheGamer). It doesn't appear to be the case, but Jones did have something to say about the other models "As far as the scientist, I took the biggest visual cliche of what a scientist would look like and went from there [...] The one you mentioned that looked like Einstein? I think I got the inspiration from George Washington (weird haircut) - not sure why."
Looking at the two side-by-side, it's painfully obvious. Especially when looking at the HD models from Blue Shift and Opposing Force. The only thing Washington is missing is the moustache, which is probably why Einstein became the more popular comparison. That and because he's a famous scientist, which fits a bit better than an American president.
Over the years, Half-Life fans also dug up a cut female scientist from the alpha, whose textures can be found in the Source version of the game's files. In the initial build, she was to appear as a head scientist in the Communications Center, giving us the quest to align a satellite. However, upon returning, we would find that she had sold us out to the HECU. This was cut and repurposed for Judith Mossman in the sequel, who sells us out to the Combine.
Jones corroborated this discovery, "The other [scientists] fell into place, just looking for more variety at the time [...] It would have been fun to do more. We did have a female scientist, but she did not make it in."
He also confirmed a popular fan theory that G-Man is based on X-Files' Cancer Man (or Cigarette Man), something that the community has long thought might be the case given that the original game launched at the height of the show's popularity. "I do know for a fact, the G-Man was loosely based on Cigarette Man from X-Files," Jones tells TheGamer. "[Valve founder] Gabe Newell mentioned that's what he wanted to see. X-Files was huge at the time, so the design followed."
So, all along, Half-Life was about a ginger scientist saving President George Washington while Cigarette Man watched from the sidelines.