Great post! As for #3, my secret is that I always work on a time-and-materials basis. If I'm, say, ghostwriting a book or developing a training intervention, I quote my hourly rate with an accurate project estimate, shake their hand, and tell them that they can use me for as few or as many hours as they wish. (Usually it's many.)
Yes, I know, you can probably pack more added value in a project estimate. But those few times I've been talked into fixed-cost projects, I have always - always - lived to regret it. Hourly or daily rates = happy clients and happy consultants!