Hello Dave and Tina,
If it is any help I took the same scene twice but with one exposure reading from the shadows and one from the highlights (both taken as spot readings). This gave two pics, one of which was underexposed and the other the opposite. This helps to illustrate which is best for recovering detail- an underexposed image or one that is overexposed and helps you being able to answer Question 4.
Hope this helps,

Peter