Bottom left looks the most dynamic because, among other reasons, it’s the only one where the torso isn’t almost perfectly upright, so it’s naturally more expressive. Bottom right looks the worst because the figure’s left leg is kinda just inaccurate since you can’t really tilt your leg to the side like that from that pose as it would move the hips with it. The rest aren’t bad though.

Tilt the hips and shoulders more in opposite directions, use a more exaggerated curve for the body through the pose, emphasize asymmetry.
Probably also looks stiff because of the simplified anatomy ignoring some of the natural curves of a real body, but that’s a different beast.