One final set of answers.

Is there a way to forestall a full-blown revolt by taking the initiative and voluntarly making some concessions, i.e. converting from an absolute monarchy to a constitutional monarchy?
Only way to change government type is through revolution. Though you can of course try to repress unrest by sticking lots of troops in a settlement or by lowering taxes for different classes, or even by exempting a region from tax entirely.

Also, I'm curious as to how the Spanish Succession is handled in the game, as it happens right at the beginning of the period covered. Does it always spark a war? Is it even an issue, or is it completely ignored in the campaign?
Wars of Succession do happen in the game. If a monarch dies without an of-age heir, another faction fo the same religion will claim your throne.

Which language do your Swedish units respond in? Actual Swedish, accented English or something else?
Swedish.

Does Sweden have Finnish regionals? Does Denmark have Norwegian regionals? I.e. distinct units associated with those regions, like Finnish light cavalry or Norwegian ski jaegers.
Sweden get Hakkapeliita, and there is one Norwegian regional unit.

My question is; will you be able to choose if you want your invading army to damage farmland and buildings? To me, if you think you can take the province quickly, you may not want to damage the assets.
You have to occupy the slots in order to cause damage to them so yes you can just ignore them and go straight for the settlement.

AI:
Have other factions gone to war during your war? Ex: France goes to war with England etc.
Yes other factions had gone to war with each other. Cannot remember all the ones that happened, but I do know that France and Spain were at war with the United Provinces.

Diplomacy:

If another nation goes to war and is our ally do you get a message asking you to join them in the war, similiar to the past, or is it just assumed as a ally you are in war with them?
Yes you get the message. However if your ally is attacked and you don't help them the alliance will be broken. If you ally is the agressor and you don't help will stay.

Other Factions:

I saw no mention of Russia, have they just been quiet up in the East?
They had been busy in the causasus area and in the Crimea.

Ministers:

Are your ministers well liked? Do they affect different areas? Ex: A good minister of defense improves morale of troops or something.
Yes I am lucky to have a good set of Ministers. Ministers give benefits/negatives to various things such as Tax Income fo Treasury Minister, or upkeep cost for Army Minister. They can also get traits that affect the happiness of classes.
Did Sweden start with 4 or 5 provinces?
4.

Did you have Pomerania at start?
No they do not, what would be Swedish Pomerania is part of a larger West Pommerania province that Prussia control.

Courland must have been the most attractive to attack but were there other minor powers possible?
Only minor faction on my borders. Other bordering factions were all majors.

Did you have any Special Units you can think of and discuss?
See answer earlier in post.

These will be the last questions I answer in this thread, I hope this has been useful and informative for you all.