The reason that Dan Dailey sings "Friendly Island" in such an odd voice is that he is making fun of Ezio Pinza the basso profundo opera star who was starring in the then current stage show "South Pacific".
During the Cosmo Cosmetics number, all of the monitors in the television control room are in color. Expensive color sets would never have been used in a real TV control room, and in fact weren't even available in 1950.