I've not heard of or seen such granularity of rules unfortunately....
You might be able to use the API to export the content so that they can review it outside of the Adobe interface? I haven't used the APIs to do this, but I know you cab export things like your metrics and dimensions, your segments, and a lot of other things..... it might be worth looking into?
Here is my 2 cents on the "only one Admin" thing.... that actually seems kind of dangerous? First off, if someone hacks or gets a hold on that ONE Admin account, you could be completely locked out of all access while the hacker has the only access...
Or if something happens to that person (they go on vacation with no access to email, are in the hospital, or they die suddenly) no one else can get in....at least not without jumping through a lot of obstacles.... I understand wanting to lock down admin to trusted people... but limiting it to a single person sounds a little extreme.... I always want a few other people to have access just in case.. they don't use it often, but it's there in case its needed....