Something I've noted: Pegasi seem to be a little touched in the head. Maybe it's flyer pathing, but... well, a familiar bug from vanilla is "Dwarf cancels construct building: creature blocking site" when they try to build a wall, statue, window, or other movement-blocking building on top of themselves for some stupid reason, at which point the build needs to be cancelled and re-ordered because every builder who tries thereafter will do the same thing otherwise.
Pegasi do this ALL THE TIME. It happens very rarely with Earth Ponies and Unicorns (I've yet to see an alicorn to test my hypothesis that it's the flying), almost to the point where they seem smarter about it than dwarves, but I've been sorely tempted to rename one of my pegasus masons "Ditzy Doo" or "Derpy" because of how far she's delayed some of my projects by building on top of herself over and over and over... If she weren't legendary, I'd disable her masonry, and in fact I've started picking grounded ponies preferentially for labors that involve building constructions.
I have to say, though, I'm doing this error reporting because I'm REALLY enjoying this mod. I'm not a good modder, but I hope that if the originator is MIA as was mentioned a couple comments back, someone takes this up and keeps it going.
RE: Armor. I've noticed the lack of proper shields too. It looks like buckler or bust.
RE: Monarch. I believe the arrival conditions are hard-coded. you can change the 'arrival' conditions for Land Holders (Baron, Count, Duke), but I see no details in the pony entity entry that determine