Mijostyn, I would take issue with a few of your points, but I will settle for this one as being the most egregious: "According to the equation the kinetic coefficient of friction changes with groove velocity"
Please show me that equation from a reputable source. As you are probably tired of reading, I have been saying over and over again that the friction force is independent of velocity, once the stylus is "moving". I only base this statement on every single physics reference I can find. So I need to see a reference to refute the notion. For all objects at rest, there is a quantity some call "stiction" or static friction, which is a way of saying that you need to put in a bit more energy than just enough to overcome friction, in order to get a body moving from rest. But otherwise, all is "kinetic". So there is no need to stipulate "kinetic".
On a separate note, I agree with MC that overhang does have a lot to do with the skating force, as it, combined with headshell offset angle, results in a constantly changing net Tracking Angle Error across the surface of the LP. Without the constant variation tracking angle error contributed by overhang, total TAE would be a constant, because the headshell offset angle is constant. Therefore, the skating force would be a constant, excepting the effect of groove tortuosity. Even at the putative two null points that can be achieved with an overhung tonearm with headshell offset, there is still some skating force. THAT skating force IS due only to the headshell offset angle, for those two instances in time. Underhung tonearms (which never are built with headshell offset angle, in my experience) do give zero skating force at the single null point available with such a tonearm, thanks to the absence of headshell offset angle. At the null point, underhung tonearms behave just like a SL tracker.