Cornwall!
Ideas towards production, morale regen, goods produced, stability cost, religious unity, infantry ability and maybe leader shock. I'd like to fit reduced autonomy in there, but IDK
Catholic religion
Not decided on Black and Gold or Black and white flag just yet.
OPM would be a hard start, but catching England in the middle of the HYW and the war of the roses could be interesting, sneak some land from Ireland and go from there
Kernow, I'd be interested in trying this out too.