1. It's a sort of excuse for the second part. Also, this is very much privilaged information. If Flax wer to announce this now his territories would face sanctioned or opposing Lords might start the jolly Medievel war early. Think about it, if he's not on-planet the other nobles won't stand for it. There's some other stuff but basically he needs to be on Agamar fo this to work.
2. Not one planet, two entire sectors would be distabalised.
Bassically, to minimize loss of life in a situation like this factions engage in Tourament.
The Planet is devided into terretories and battles are fought on pre-designated battlefields with strategic importance. This prevents wars from spilling over to the civilian population and avoids nasty things like orbital bombardment.
Concievably Flax Might have to fight 30 or more battles. This would mean that two fair sized sectores will be in ecenomic shutdown for at least a few months.
This will send ripples of de-stabalisation outwards.
(If anyone's wondering why Flax is doing this, lets just say he knows something you don't)