Okay, so, by unanimous approval the Sejm will be quickly consulted regarding the nature of the proposed Military Frontier, while Mariana will (narrowly) be getting a shiny new horse!
This leaves us with our two tied options...
[] Arrange a meeting with Jan Zamoyski.
Try to arrange contingencies for the victory of either side, to ensure a peaceful transfer of power. Tempers are running high, after all.
[] Hold a summit with some of the striver-families: the remnants of the mighty Tarnowscy, the Ruthenian Wiśniowieccy, Hetman Mikołaj Sieniawski, etc.
Remind them of the promises, the opportunities, the ease of manipulating the young Archduke: Mariana's web-weaving has perhaps planted the seeds.