Help with editing start of a new game

[Play2Jens]

Hi all,
I would like to edit the start of a new game. These are the following things I'd like to edit:
- Change the starting message.
- Start with an intact part of your crashed spaceship on the map. 
- Starting pawns all have the same uniform.
- Starting pawns are a random variable between 2 and 6.

Can I edit this in XML, or do I need to work in the core script of the game?
And is there a mod somewhere which adds different races?

This will be my first attempt on modding, but I did some programming courses in school.