It's going to be an uphill battle for her to make the case for this being a bad idea, if she has to have someone else build that case for her. Especially if the person building that case is not even allowed to be doing that work. If it's a matter off "consultant said X, our employee said Y, and gosh I really trust our employee on this one" -- fair enough. But it sounds like she's going to need to present these ideas as her own, without really having a basis for coming to the conclusions she needs to present. I don't see it going well.
Side question: If this person reports to her, doesn't she have the authority to evaluate their performance, or even stop them from doing crazy things in the first place?
Side question: If this person reports to her, doesn't she have the authority to evaluate their performance, or even stop them from doing crazy things in the first place?