It's been so long since I've teen the cartoon, but I vaguely remember Destro and Baron being either Hyper Competent Sidekicks, The Watson, or Meta Guy to Cobra - or at least having little more competence then him being the General Failure. Anyone?
Adult Child has been renamed to One of the Kids. In order for this to be an example of the trope, the character's childishness has to be from or demonstrated by interacting with children. This example can be added back with context relevant to the trope if it fits.