I highly doubt Lucas had anything to do about these different Gungan “races”. Pretty sure that was all in the EU.
Of course George had something to do with it. He approved every design in the movie! The EU didn’t make and then approve the character designs.
I was referring to there being two Gungan races as an excuse for the different appearances. Of course Lucas approved of their appearances in the movie. What’s been bugging me is that Lucas approved of three variations of the design, yet the EU only explained two of them, despite their tendency to add an overly complex explanation and backstory to everything.