Well off the top of my head ive got nothing. I suspect there will be nothing more official either but i feel like a bit of speculation today so i might have a read and see what comes to mind.
Oh yeah, the eye of Myrkul adventure. I've always wanted to run it. It was written by Eric L. Boyd and was chock full of lore.
On the crowns, just in case you can't get ahold of that copy, it says that the crowns were crafted Iniarv, the oft-absent Mage-Royal of Uthtower, for the twin Princes Uth II of Uthtower and Ornoth of Yarlith when the kingdom was split between them after their father died.
Its rumored that Iniarv enchanted the crowns, because the two monarchs ruled capably, never disagreed and both died peacefully in their sleep at an old age in the same year (whether they died at the same time isn't noted).