Are you thinking Thayet will go mad and cause problems? Or that Roald will become increasingly unstable, so that when Jon dies he'll know he's leaving the kingdom in the hands of someone who can't possibly run it?

And no, of course marrying off all the Conte kids out of the country won't make peace! Not that this stopped people from trying that strategy historically, either, mind you. At least it means that they aren't home to plan coups, though.

I'm thinking Aly's plan would be to manipulate the Isles into becoming a vassal state of Tortall's. But this would involve a rather involved AU.