First Half of the Alternate Character Interpretation prompt.
From left to right:
Hosanna Cutting-Green: previously seen in the Personal Space picture, usually the daughter of a deeply sexist human culture.
previously seen in the character sheet pictures, as well as the currently defunct Staff. Usually female, from a species with a huge gender imbalance.
Chren and Mehrn:
Not from an art challenge yet, but from the ongoing Skyfall comic. Members of a species with very few reproductively mature individuals.
More about all this on the blog, of course of course.