Let’s make things clear: whether Kaidou, Whitebeard, Big Mom, and Shanks have that specific application is subjective. After all, Kaidou never had to face an immortal being to prove such a capability. However, there are signs and even strong chances that all the members of the Rocks Pirates were aware of it, since the Holy Knights were present at God Valley.
The main point is that Kaidou and Big Mom meet the minimum requirements for this application. And what are those minimum requirements? Possessing CoC, and more importantly, AdCoC.
The situation with the admirals is more complicated, as they don’t even have the most basic requirement needed to build a hypothesis in the first place: Conqueror’s Haki itself. They’re the ones who are truly at a disadvantage.