1. The Empire and Stormcloaks grind each other down then the Thalmor incite the Falmer to start increasing their night time raids.
2. #3
3. Yes
4. Killed off
5. Herma-Mora drags him off for a few thousand years
6. The blades get butthurt that the Dragonborn wouldn't bend over backwards for them and kill Parrthurnax so they go sulk before being killed by the Thalmor.
7. Dawnguard win otherwise TES:6 would be kind of annoying without the sun and even worse magic system then Skyrim.
8. http://nooooooooooooooo.com/
* If Skyrim becomes independent, High Rock is cut off from Cyrodiil. Cyrodiil's economy will be reeling from the war and loss of trade. The Thalmor will devour them. So, the Empire is fighting for its continued existence. Also, Ulfric doesn't even have support from all of Windhelm. If the Dragonborn has a brain, he knows that a victory for Ulfric effectively adds Cyrodiil to the Dominion.
* The dragons do massive damage, but are ultimately killed off, except for the ones who follow Paarthurnax's Way of the Voice. The ones that do coexist (albeit uneasily at times) with mankind.
* Since the Dark Brotherhood questline is poorly conceived (they recruit you for exterminating the foulest individual in Skyrim), and since the Dragonborn's not going to kill the Emperor of the Empire he just helped save, my answer is no.
* The Dragonborn dies when the Thalmor invade Skyrim.
* Since relatively few players are willing to kill Paarthy (a disgusting quest, if I may say so), I say he lives.
* Don't have Dawnguard, so I can't say for sure. But suns are not easy to destroy...
* Not even going to speculate on who the Dragonborn marries.