Grouping people into types is pretty common. You can call it "joker", or INTJ, or a blue parachute. This particular grouping is cute but not the point. What I found interesting was the assertion about how behavior is likely to change as things get tougher, and how behavior should change. Their claim is that people will moderate their behavior as things get tougher - the joker will make fewer wisecracks, the realist will get more pessimistic, etc. Further, they assert that it will only make people more nervous; instead the joker should keep joking, the realist should keep pointing out both risks and opportunities, etc.
There's one thing that immediately leaps to my mind: it's really easy to say "we should". It's often a lot harder to actually do it. And the report offers no ideas for how to achieve the things we should be doing (presumably the longer private report does).
Knowing what you should do is only the first step. It's no good without knowing how you are going to achieve it.