This is an interesting dilemma you brought up. I think you should divulge as much information as possible under the protection of the Non-Disclosure Agreement since it will be very difficult for the Consultant to help you if you don’t. In order to solve your problems, they need to be able to have access to a large array of documents and information. The less they know, the longer it will take to get any relevant feedback to improve your company. It is in your best interest in regards to time, money, and quality to work with the Consultant as an ally and not someone trying to steal all your secrets.