mini-comics (series 1 and 2). As soon as the concept of Prince Adam is introduced there is no more talk of the two halves of the Power Sword.
As for talk of the Skittle-colored swords... we haven't actually gotten a color we should have: fiery green!
He-Ro's blue Power Sword is an homage to the Blue Battle Armor He-Man Power Sword from the Weapons Pak. Plus, he brought it to Eternia; it can be whatever color he wants.
Skeletor's should be gray/silver, but I'm guessing part of the reason the original toy came with purple, just as Faker came with orange, due to the way the toys were manufactured in the early 80s.