Two-die sets are for bottleneck rifle cases. You have one die that resizes, decaps and expands the case mouth. The other die seats the bullet and applies a crimp (if you want one).
Three-die sets are for straightwall pistol cases. You have one die that resizes and deprimes, one that bells the case mouth, and one that seats the bullet and applies a crimp.
Lee makes three-die sets for rifle. The third die is a separate crimp die. They also make four-dies sets for pistol. Again, the fourth die is a separate crimp die.
Powder? Not for the two rounds you want to load. Unique is called unique because it can be loaded into rifle shells, pistol shells and shotgun shells. BUT, it won't work with all of 'em, and it won't work with 223.
You will need two different powders, and two different primers - small rifle and small pistol. They are the same size, but they are not the same, and are not interchangeable.