1. Genghis Khan: In VEM, you get 50 alliance turns' worth of instant
Food,
Culture, or
Units if you're the first to capture a City-State. (I'm not sure if subsequent conquerors do...) So Genghis gets 25% more, or 62.5 turns' worth of benefits, upon capturing a CS.
2. I believe it's 100
per discovered NW, at least on normal speed. Less luck-based than vanilla.
3–5. I like those proposed difficulty descriptions.
Maybe something like "Don't hurt me..." instead of "Cakewalk" though.
6. Yes, I've asked this question before. As Thal pointed out, you can simply go to Options on the Main Menu and move the tooltip timing slider to the left.
7, 8. One of the most annoying things about Vanilla is how the same blue symbol can mean either Friends with at least 60 Influence or Allies. Have you tried
CivWillard though? It gives you access to highly customizable information screens that are interactive as well (i.e., click the Ivory icon next to France to go directly to the trade screen and ask Napoleon what he's willing to give up for it): check it out.
9. Yeah, the CS war notifications are terribly designed... although frankly, I'd rather Thal spend most of his time on gameplay issues, not UI ones.