Paragraph 1) This will depend on the needs of the players. Good luck "forcing" PCs or NPCs alike to do anything. They won't be able to unless there is a signed contract.
2) Maybe, but most objectives will be city planning/development. You may or may not get SP for putting a bakery where the city manager wanted one.
3) Nope to either of those because then the non-participants would become participants in the developing war against whoever would be trying to do that. This won't be like the movies/tv, not everyone packed up and went to war. Basic needs still must be tended and if everyone is at war no one is working to pay the taxes of those off at war. Actually it would make more sense to tax the soldiers because non-participants were the only people paying taxes during the war. Families left behind still need food, so someone has to farm. War must be supplied so someone has to craft. Stuff like that. Anyone trying to rally "every able bodied man" isn't fit to rule because they're an inbred noble with a defected mind.