2. Is indeed in the serverconfig.txt. (In the root folder of your world). Change that using notepad and either restart your world or type *reloadconfig
What exactly do you mean by starting a game? Things like battlezone that have an auto-reset timer use the wargames modes to automate the game start and end. For an econ island theres nothing really to do other than start time moving (*settings -> World -> Daylength - it defines the number of seconds per gameday).
Ultimately planet textures will be configurable and downloadable from the galaxy server. I'll have a look at manually changing yours for the time being..