1. search for skeletal mesh in the content browser! Also did you see JordanW's technique of blocking out a brush man?
I like that it doesn't look as out of place as the available character models.
2. in editor, pressing ctrl+1 (or ctrl+2, or 3 etc.) saves that camera angle, and pressing 1 (or the appropriate number) returns you to it! Just like an RTS! There is a camera actor and a little bit of kismet love will set it up, but I have no idea how to off the top of my head right now! (let me know if you find a good link!)
3. fog is a good start but post processing is even better. I can't recommend a specific free tutorial as I've been using the eat 3d UDK lighting and post processing DVD all day, but it's not much of a stretch (and fairly well documented) to set up a post processing chain that would make brightly lit areas bright and light blue, whilst shadow areas are desaturated and orangey brown.
Haha, your actually asking all the questions I was asking myself earlier today! So I'm not a massive help, but hopefully that should get you started.
edit: to answer 3 a bit more, if you look at your references theres alot of light, bright, sunlight with warm reddish-brown diffuse colours. If you follow Tekkonkinkreet as an example it's a very run down city but created using a very warm and saturated palette.