1. The first crisis seems to begin around day 100 if it’s the war, and 75 if it’s the greenskin crisis or undead invasion. In my playthroughs, the next crisis seems to begin the same amount of days after the first since the beginning of the previous crisis. Could be wrong about that one.
2. I do believe there was a stat tweaking a while back, but I can’t swear on it. You might want to check the blog history. I want to say high stats were reigned in, but sometimes I can still hire a good militiaman with high melee or ranged skill.
3. Only good way to fight these bastards is to have a very high level sergeant with “Rally The Troops”, or a soldier with the anti-fear undead trinket. You can get that item by completing the Destroy Undead Locations ambition, but it makes the brother wearing it immune to fear effects. While your front line engages and distracts, you send him to destroy the geists. Ideally, it’s a brother built to fight solo, since there’s the chance that he’ll be intercepted by other enemies. I’ve seen people mention range as an alternative, but geists have unreal defensive stats against ranged attacks.