How can the time length of about 5 moves, when going into anarchy when changing govts., be lowered in the civ editor?

I don't think you can change this. It's random. From what I've heard, if I remember correctly, its anywhere from 1-12 turns. The only way around this is to be a religious civ, that makes it only one turn of anarchy, gauranteed.

I looked for this option too, but the only thing I found in the editor was something that sets a turn limit for anarchy for the AI, not the human. You can do the AI thing in the Rules section under Difficulty Levels. Unfortunately, there's currently no way to change the human number of turns.