One thing you shouldn't do is sleep on the importance of the audio engineer.. Often times at the studio, the engineer will get asked to teach and share the knowledge. You shouldn't be in your feelings if they aren't all ready to give up the keys to their quality sound. Let us not mention the added headaches necessary to even receive credit on werk they completed.  We have a starting point for you and the Engineer's Corner assembled of the Patchwerk Recording Studios audio engineers is a great look.