[jc173]

I am not exactly sure what the tone does it may affect the chance the AI will accept a request from you depending on how different your scores are. Then again I might have that backwards sorta, I might be thinking of the setting that determines what tone the AI will use with you.

If you dig around the AI's settings/politics files it does list the percentage chances of the AI's accepting different treaties according to your score differences.

For the third part there's a minimum time that must pass after a war has been declared before the AI will accept a peace treaty. However, I think there's something buggy in those subroutines because in the past I have seen brotherly AI's refuse to accept a nonagression treaty or trade agreement with me.

The major factors in the AI's politics seem to be it's anger level/attitude towards you and the difference in your scores.