:::::::::::::::::1. Again, Valentino does not consider Afghanistan in the "Communist mass killings" chapter, that means he discriminates between "Communist mass killings" and "mass killings under Communists". If we exclude such "episodes" as GLF or Great Soviet famine, and Rummel's mythical 40 million Gulag deaths (which is not taken seriously by any specialist in Russian history), the figure of 110 million will dramatically collapse. Lion's share of the "episodes" considered by Valentino were not mass killings in commonsensual understanding of that term. And, do not forget that Valentino didn't work with primary sources to determine the scale of mass killings, he simply compiled the results of others, so he is a tertiary source for the figures. 
 :::::::::::::::::2, 3. Great. 
 :::::::::::::::::4. Sorry, I simply misread you. If you meant morality, you seem to misread Courtois. As Hiroaki Kuromiya (Journal of Contemporary History, Vol. 36, No. 1 (Jan., 2001), pp. 191-201) says 
 :::::::::::::::::::"What is implied in The Black Book is that distinctions between direct and indirect killings are fine points of no consequence and that the crimes of communism are far graver at least numerically than those of another totalitarian regime in the twentieth century, nazism, whose casualties were a quarter those of communism. " 
 ::::::::::::::::::in other words, Courtois' conclusion, contrary to your assertion, is based exactly on the figures, and his "playing with figures" (Kuromiya's words) is aimed to confirm his point that Communism was much more horrible then Nazism. Therefore, all of that - (i)combining indirect and direct deaths; (ii) obtaining the figure of 70+ million killings; (iii) coming to conclusion that Communism was more horrible than Nazism; (iv) criticism of this idea - must be presented in the article in the same place and in a context of each other. 
 :::::::::::::::::5. For example, whereas Courtois writes about "Communist genocide in Cambodia", many authors prefer to speak about national specifics and historical background of the genocide perpetrated by the adepts of weird agrarian Maoist ideology with strong smell of racism and fascism, and to show a dramatic difference between Khmer Gouge and, e.g. European or Soviet Communists. The problem is that such authors never tried to come out with any combined estimate of Communist death toll, simply because they see no much reason for that (no significant commonality between those events). 
 :::::::::::::::::6. We have many sources that discuss motivation of the authors of the BB, and of Courtois in particular. My conclusion is based on that. Similarly, motivation of Rummel is dictated by his libertarian views (I don't remember where I read that, but I can try to find).