Lots of anatomical detail which i don't know at the moment. LMAO.
But I do know about centre of gravity and I feel that second pose is a bit uneven as the character is putting a lot of her weight on one side which eventually leads her to fall down! Central of Gravity is normally a straight line between character's both feet and a character is balanced if there's equal weight distribution between the line.
So for this example, to be even she can:
- Tilt her torso the other side (opposite)
- Have a standing leg further away from the centre to offset the uneven weight distribution
Have you tried looking at contrapposto? Maybe that can helps you draw pose from imagination.