I think it's more likely the Fjord baronies have a parliamentary monarchy-they definitely have a King. So basically a hereditary oligarchy, but more structured. Like England, if you surgically removed the House of Commons.
I've always viewed Yesha as much like Imperial China, with the addition of a caste system. An Emperor, yes, but also a vast bureaucracy, with civil service tests to determine your role, and possibly secure advancement. It would be hard/impossible to move outside of your assigned caste, though you could advance within it.
Anglea might have a sort of tribal moot-the tribes elect a head, and the head represents them within the Althing.
The Mercentile guild, on the other hand, is interesting. I keep going back to Venice for a model for their government, with a Doge/Prince that is chosen among various great corporation-houses.
Chalcodon is kinda a blank