As far as "Mischief", I think that is just a grammatical pun, if I say one is a Trinitarian, that does not make you 3 times the arian that Jws are. Regardless of how we translate YHWH in English I would imagine the actual etymology would be the same. "Hovah" of course is anglicized, and not hebrew. The other objection you bring up is who "coined" it, I never got this objection, obviuosly at some point an anglo form of the name would have come about , so the who would not be a decent objection IMO. True people before JWs came on the scene spoke an anglicized dialect,but that would be expected. And I had always heard that it was coined prior to "Luther". But that is a trivial objection on my part :>)
I am open to correction on any of the above.