No need for more. As I said, I'm familiar with the research because my wife and I discuss it. I read the monthly medical journals that she receives because I work with people on the exercise half of the equation and I believe in a holistic approach to fitness.
If you dig into the research, you will see a few trends - some of which you pointed out. First, do not reward a clean plate with empty calories, e.g. dessert. Second, portion size is important. Third, being overly controlling and not allowing children to develop their own cues often has a correlation with diabetes or obesity.
NONE of the research, demonstrates causation between having children eat what is on their plate and obesity or diabetes.
While there is a correlation (again, none of the studies you cited or that I have seen have demonstrated causation) between highly controlling parents - particularly where food is related - and obesity or Type 2 diabetes, it is where control is exerted past the time when the child should begin developing his or her own controls. This is a problem with control, not with cleaning one's plate. No control can be just as detrimental, leaving the child with no framework in which to make good food and eating decisions.
Given appropriate portion sizes, "clean your plate" absolutely does not force a child to overeat. Quite the opposite, it helps them understand appropriate portion sizes and, done right, how to make healthy choices. As you said, children rarely understand appropriate portion sizes themselves.
This subject is hardly as simply as the blog posts and articles that cited the research made it out to be.