Can you create a scenario for 1 player and have the computer play opposing civ?
of cource!
you can be any civilisation and fight against all or one civilisation, you can even both be the empire or rebels etc
you can, but you'll have to give the computer 'directions' if you want the scenario to play out a certain way.. it's called the 'trigger' system.
i think i am missunderstanding this.
either way leon will die:) well tirion first
If you are creating custom maps, the trigger system is essential. If you just want to create your own version of a random map, then the trigger system is not always needed. Another aspect that you should look into is AI scripting. AI, beyond triggers, is what the computer player functions on.