I like their designs; they don't need clothes.
One concern I have though is that the blue and red minions also do not have clothes. Is this going to turn out to be the same for all characters? I don't want the game looking generic, which is how characters without clothes often look. On the contrary, lots of characters in the Banjo games had some type of distinguishing clothing, such as Klungo's lab jacket and Grunty's hat/scarf etc.