I think your points get at Belyaev's original intentions for the experiments. His papers are not so much "wouldn't it be cool if we could domesticate foxes in just a few generations", but speak much more to the fact that, as you select for behavioral traits, physical traits are sort of unintentionally selected. The interesting thing about it (though I don't think Belyaev said this) is that the domesticated physical traits tend to be "cute" by our standards. For example, the domesticated foxes have proportionally wider skulls, which I can't help but read and think about this:
http://www.exploratorium.edu/mind/judgment/cuteify/v1/