The first two steroids are for high potassium and the second two for low potassium intake. The first and third steroids are for low sodium intake. I believe that aldosterone's role is fairly clear, and well accepted. The others are largely speculations of mine. They all must conserve sodium in order to be called a mineralocorticoid.
Sodium makes up most of the cations of blood plasma.
Thus 580 grams of sodium and 36 grams of potassium are filtered each day. Therefore, the sodium pumps must always operate to conserve sodium. Potassium must sometimes be conserved also, but since the amount of potassium in the serum is very small and the pool of potassium in the cells is fifty times as large, the situation is not so critical for potassium. Potassium is secreted twice and reabsorbed three times before the urine reaches the collecting tubules. At that point, it usually has about the same concentration as plasma with respect to potassium.