I've since watched a bunch of Proko ['drawing human anatomy' videos] repeatedly (and will continue to) and I decided to do Starfire.
The character is in a pose I felt was appropriate for a side scrolling shoot 'em up. Starfire is known as a happy character, so I used light colors to reflect this. The theoretical game that came to mind was something like Fantasy Zone, or Panorama Cotton.
I scarified the green for the eyes for the sake of a darker shade of purple so the overall sprite would look better. Without the shading, it looked like a big blob, to me, anyway.
I've included my own sketch (sorry if you can't tell what you're seeing), a reference picture and my own pixel art.
Starfire reference picture (very large pic):
https://i.imgur.com/6of95L1.jpgSketch (very large):
https://i.imgur.com/PzPqDyN.jpgI had second thoughts for the pose. Instead of Star facing backwards, I decided that I wanted her to face forwards.
Pixel art: