Hachiman is pretty much the same height as Lion-O as seen here: And I think Safari Joe is around that height as well. However, Hachiman isn't human because he comes from the Planet of the Red Sun. And I don't think Safari Joe is from Earth either. He could be, but I don't recall anything in the episode specifically mentioning that. He is portrayed as kind of an intergalactic hunter, and all his tech hints that he isn't from Earth. The really "true" humans would include the Warrior Maidens, King Arthur, Merlin, Queen Tartara and her Guards and Dr. Dometone and is crew (there could be more but I can't recall right now). As far as I remember, the Warrior Maidens and Queen Tartara are around Cheetara's height, so according to the production material, they were all around 6 feet tall, which is a bit too tall. My guess is that even though they originally designed the characters to be a bit taller than the average human, in the final animation they made them around the same size as normal human superheroes, either because it was easier to do so, or perhaps they forgot to do it, or maybe it was just visually better to see the heroes as normal-sh than as really tall beings. Again, this is just my guess.