(incomplete list of stances)
There are some rules common to all stances in TKD: Hold the back upright, this is important for correct techniques, as well as your healthiness. The knees aren't completely stretched, so you are elastic in your position 2.1.
The feets are parallel, closely put together. Normally the eyes look forward, in the same direction as your toes. The bows at the beginning and end of each training, as well as to your partner are done in this position.
Feets are parallel with a distance equal to the width of your shoulders. Arms are circular before your body, fists closed, in the height of your belt knot. The fists have a distance of around a width of a fist, and are the same distance before the body.
This position is more like riding on a horse, than standing. The feets are parallel, with two shoulder-widths distance. The knees are bend, stand deep.
This stance is one shoulder broad, the length should be more than one shoulder width (around 1 1/2 - 2 * shoulder width). If possible the feets are parallel, the back feet could be turned somewhat to the outside. The back leg is strechted, the front leg bend. Your center of gravity is in the middle between your feets. The hip is turned forward, so that the axle through both hip joints is ninety degree against the movement direction.
You get Chongul-Sogi, if you stand in Narani-Sogi, and then put one of your feets straight forward (or backward) the steplength.
This position is like an L. One foot points forward, the other ninety degree to the side. The distance between the feet is again the width of your shoulder. Both knee are bend, the center of gravity is more at the back leg, around seventy percent. Your body (and the hip of course) points to the side, so you did have an small silhouette.
In Kyocha-Sogi your center of gravity is completly on one foot. This leg is somewhat bend. The other leg is crossed before or behind the first leg, and just tips onto the bottom with the ball.
This position is like Hugul, but the front leg is pulled back, so that there is a maximum distance of one foot width between the heels, if both heels are on the bottom. The foot of the front leg only tips with the ball on the bottom. The center of gravity is of course over the rear leg.