1. You have to gain Influence. Usually done easily enough with events or by conquering planets.
2. If you click on your character in the station it will open up your character screen and near the bottom, just above the export option is a customize option. You can change everything about your character, face included.
3. The type of room/tile you can place changes depending on what "area" you've selected. Clicking on open space or the back button gives you access to basic area tiles, while clicking on an area tile will give you more specific rooms for that area. Ie., placing brothel tiles down then clicking on those tiles will let you place private rooms etc.
4. There are, like, five different sliders for 'scrotum' and I really don't know what the difference is between them, but I don't believe there is any way to edit pubic hair for some reason.
5. The animations are completely janky and they don't get any better. On the bright side, Stationmaster 2 is in the works and should have much better animation.
6. It just goes in the main folder with the exe file and everything else. You should get a prompt to enable it when you start a new game.