The tooth fairy example gets a variety of responses

Seriously? I've never heard anyone insist that the tooth fairy really exists (in the form of their mother). It would seem most contrary to common usage (in my community, at least) to use 'Tooth Fairy' to denote "whoever replaced the tooth under my pillow with a coin". The magical element is (in my experience) treated as essential to the term and not a mere "connotation".

I've heard of the saying you mention, but I think you misunderstand people when you interpret it literally. My response was not intended as some "peculiar" declaration of mind-independent meaning facts, but rather as a straightforward interpretation of what people who utter such claims have in mind when they do so. (Ask them, "Do you mean that the tooth fairy exists?" and I expect the response, "No, silly, I just mean that my mother is responsible for the coin under my pillow.")

So, to clarify: I don't think that there are free-floating "meaning" facts out there independently of our linguistic dispositions. I just dispute whether your definitions adequately capture the things that most people really care about (i.e. treat as essential) when using the terms in question.

It's no excuse to say that metaethical reductionism "gets reality right" when the whole dispute is instead over whether they have accommodated (or rather eliminated) some concept of which we have a pre-theoretic grasp. Compare the theological reductionist thesis that "God is love". Love exists, therefore God exists, voila! If someone pointed out that this view is needlessly misleading since love is not what most people mean to be talking about when they speak of 'God' (and it would be more honest to just admit one's atheism), it would be no response to give a lecture about constellations and tinkerbell.