George is a smart, small one, Junior is tthe big, dumb-headed one, who gets disiplented by George for any stupid thing Junior does by simply kicking him in the butt.
They are simply Neutrol characters, cause while not with the louge, it's clear they aren't with the leage or other villain teams because they later appeared after Scroop and Deadpool left, or that they didn't showed up with them, or did they had other villains with them.
It was eventually revealed in the epilogue that they were hired by a mysterious hirer for Mysterious reasons. Some guesses to the person who believes it may be Emperor Fang, since he's already got some Tex Avery villains in his possession, Pal & Joe, but Scroopfan saids it's not, but also won't revel who the Mysterious hirer is...right now. But when he will reveal the true identity of the boss is also a mystery.