Re: ...delightful cakey accompaniment is pronounced "scone"...
That's a third way then. Though not actually one I've ever heard.
"Scone" pronounced to rhyme with gone I have heard, often.
"Scone" to rhyme with tone, a bit less so. Down my way it was people trying to sound posher than what they were said it like that.
But to rhyme with gown - nope, never. Unless you mean "own" which does rhyme with tone/bone/phone etc.