I'm of the persuasion that thinks there is no useful, universally accepted definition of "scripting language." Even if we did pick one of the various common definitions and stick with it, I don't see the point. I think it's far better just to talk about languages in terms of their concrete properties, rather than trying to come up with strange, arbitrary categories to fit them into.
That said, your post does indeed talk about some concrete properties of various languages. Because of this, I think it's a pretty interesting discussion, but the overall purpose -- to find a "good" definition of "scripting language" -- strikes me as odd. Hopefully you'll see my post not as poo-pooing further discussion, but rather encouraging the kind I think is more useful. :-)