Perhaps you are right ODDBODD because i too remeber seeing the other mudokons with blue colored skin. Funny though that the BigFace was not blue nor the natives in the ending movie. And in AE there were no blue mudokons other then Abe and the same with MO. Perhaps it was the lighting in rupture farms that gave them that color. And im sure not all of the had been through a Paramite juice bet. And yes we do know that Abe was not depressed because he liked his job. I just think it was the lighting of rupture farms.
So i go with the chosen one theory.