Process of Head Coach interviews (merged)

I've always been curious about how the HC selection and interview process works. In my professional life, I've been on several interview panels and have been interviewed by panels, but I doubt my experience in any way reflects how it works in professional sports, particularly the NFL.
Anyway, it would be fascinating to know how these discussions work and how evaluations are done. Or, I'm probably overthinking it. It may be as straightforward as, "I know <insert preferred guy> and he's my choice. I'll listen to the others, but unless I'm blown away, he's who I want to move forward with."