I really like the idea of variations, so if that's something practical for the game, I would love to see it added.! If it's just as much work to add an entirely new character, then just do that of course, but I imagine it would add a lot of variety without causing too many problems. This feature would absolutely cause me to spend more time looking for the perfect specimen to take pictures of, and would sort of act as a method of personalization, by letting you make more choices off of visual preferences.