The lack of any such list/video has struck me as "not right." Assuming there is some value in having the demonstrations be done slow, exaggerated and with very specific points highlighted, why aren't they done that way on the OW video?
Two questions, the first is answerable - not sure about the second.
In anything other than a very general sense, the "critical attributes" of a skill will vary entirely depending on how the skill is done. Well, I say "skill".... I should say "how the performance requirements is achieved".
PADI never really say how a performance requirement needs to be achieved, just what needs to be achieved. Take "deep water entry" from CW2, for which the PR is something like "In a controlled manner, enter water too deep to stand up in".
Here, almost every instructor teaches a giant stride for this and will 'ping' DMTs for doing something different in their skill circuit, even if the DMT does a good entry using another method!! But even the critical attributes of the giant stride will vary - so I would tend to emphasise the need to have some air in the BCD, but not overly full. And I would tend to get a diver to signal OK after the entry..... both of which go out of the window if you have a negative entry for a drift dive. If that is the environment in which you teach, then the critical attributes would be to have no air in the BCD at all and to ensure group contact under the surface.
Bottom line with demo-ing skills, it just needs to be slow and made to look easy. The latter is as much about positioning as anything else - take mask clearing for example, some people push the top of the mask against the forehead using a single hand in the middle of the mask.... nothing wrong with that, and it works for many students, but having your hands in front of your mask blocks the students from seeing how easily you can slowly clear the water from your mask.
As for your second question, Peter.... no idea. I don't show the CW preview to students and haven't actually watched the way the skills are done in ages. I recall that whole section being exceptionally painful.