This was an interesting read, I’ve heard of Carroll’s “Poetic Naturalism” before but haven’t had a chance to look into it more deeply. There were a lot of points that merit a response in this post, but I’d like to just respond to a few. First, the quotes seem to lump together all forms of “essentialism,” and all ancient philosophical systems more generally. For example, in the quote from This Idea Must Die, Dawkins says “If, like Aristotle, you treat all flesh-and-blood rabbits as imperfect approximations to an ideal Platonic rabbit…” but that is most definitley not how Aristotle treated forms; his essentialism was very different from Plato’s. For Aristotle, there is no “ideal” form that exists independantly of the actual object which instantiates the form; the object just is the form instantiated in a particular arrangement of matter (this is called hylomorphism).
Your post as a whole was generally fair and well informed, with one exception: your treatment of arguments for the existence of God. No serious atheistic philosopher thinks the objection “who created God?” is valid, whatsoever (See the work of atheist philosopher Jeffery Lowder for an example). Second, God is not external “conveniently by definition.” On the contrary, theistic philosophers have given good reasons, for thousands of years, for thinking of God in such ways. And while the argument you examined is probably the most popular contemporary argument, there are much, much better ones. I’ve written a series of several lengthy posts defending Aristotle’s/Aquinas’s Prime Mover Argument. The first one can be found here: https://senshomines.wordpress.com/2016/04/10/prime-mover-an-amateur-defense/
Thanks for writing.