The consultant is being paid by management. S/he is beholden to them. If anything can be traced back to a group or individual, it will be, and it won't be pleasant for anyone who believed the request for honest feedback.
Quite the opposite. One of the reasons people go into consulting (and I don't mean working for a consulting company), is precisely because they're not beholden to them. They have much more freedom to set the terms than employees do.
If a company wants them to reveal the individual, they'll be happy to give them the middle finger and let them know their morals are lacking.
Someone who thinks they will protect you may be as big of a wildcard as someone who demonstrates clearly that they won't, because you haven't given anything really damning to the latter.
Of course there are companies where consultants do not have this happy outcome--either because management doesn't listen to the feedback even from the consultant, or because the consultant does what you describe and doesn't protect the working level people who confided in them. But the article indicates that this doesn't have to happen, and that was my point: as I said, the consultant has a shot at getting to a solution of the problem.
Yes, and if the consultant fails, s/he's off to the next gig. The author did not mention any cases where his approach failed.
The author also says "One week later, I will schedule a meeting with executive leadership, and during that meeting, I will read back a very lightly edited version of the transcript of the previous meeting"
Dandy. If one has a recognizable voice - style, usage, etc. - it will be recognized. And dealt with.
I don't think the solutions he's presenting will "scale." He says "[if you need] event-driven distributed systems consensus algorithm implemented using Twisted, I’m absolutely your guy." He's a young guy with a pretty narrow niche and is making some pretty big claims for a large world outside of it.