I think I get where he is going with this (and if this isn't what he is doing then he's retarded.)
The test isn't actually "get a detailed description of everyone involved" situation. I doubt he even opens these emails or anything besides getting grok to skim it. He even said he wants no classified/sensitive information. He's basically seeing who is a higj priority target. Making a big graph of each department's response, and the ratio of who responded and who just either sent nonsense or no response. Then he makes a big list and hits the biggest offenders first.
When I was doing acquisition management for a time we were told to provide a weekly report of what we did. Guy I reported to wasn't in my career field. I was gone at least half the time on trips for my various systems/missions. Welcomed the chance to do the reports, didn't need to be real detailed, more like one- or two-liners. Reporting official read them, asked the occasional question, then passed to our division chief, another intelligence officer and my operational supervisor. Was already doing periodic 'talking papers' on the systems/missions for info up to the four-star level.
Saw the whole thing as a win-win. My reporting boss got more info for his own knowledge, use in officer performance reports, and the end-of-tour award writeup, as did my operational boss. Didn't take long to do, paper more storable than the daily phone call I would make back while on the road.
Some weeks were busier than others. Some weeks was in the office all week getting everything done I had generated while on the road, plus staying on top of things overall, plus any little projects/additional duties. Other weeks I was gone all week doing stuff. And I took the occasional leave. Five years went fast. Time always does when you have a real job. We had our share of drones where I worked but as long as I didn't have to interact with them didn't care.
Getting one report will help Musk see who responds. The real decision as to who to fire and maybe who to promote needs to come from reading a couple months' reports. If every written report has little or nothing to report, that person needs to go. If you are getting meaty reports with a lot of shit getting done, that person bears watching and support. You want to make sure this guy or gal doesn't get overloaded, just keep the load workable. And should you get incoherent reports you cannot make heads or tails out of you know what you got...