@Seattle1Thanks as always @al66pine for your never-ending research.
Yes, statutory declaration of death means judicial resolution--with none of the two exceptions you provided applicable (i.e, SM located alive, her remains recovered).
Confirming death terminates guardianship just as with POA.

By inadvertently combining a couple different unrelated paragraphs, I bungled the cut and paste from my Word into the post.
Where is a gigantic red faced smilie when I need it?