Ideally mind map by memory, not using the book. Keep details to a minimum on a mind map. The goal is to have a little information trigger more detailed information when reviewing.
Mind Mapping each chapter is okay. Just reduce the details.
You can add to your mind map after Rapid Reading, or, after each Super Read & Dip or Skittering session if you choose to do multiple passes with these strategies.
Use your mind map as a study tool.
Yes to writing down the questions in your postview.
All the best!