First of all, you should be applauded on a well thought out, well researched argument. In response to the title, I doubt it. In some cases intelligence and the ability to reason will inevitably lead to atheism, but there are billions of exceptionally intelligent people who firmly believe in religion, this being due to the power of brainwashing a young child. Thus, I would say that location and upbringing are the primary influences in wether a child grows up to be religious or not. That being said, as we develop out abilities to think critically and reason using logic I imagine atheism will continue to rise. So I'd be happy to conclude that higher intelligence increases the probability of atheism in an individual, but not that atheists are more intelligent.
That's just my take on it.