You tell me, because I really haven't got a clue. For finishing, I find Coticules all very similar. The 3 edge qualifications I use, "Brisk", "Engaging" and "Mellow" are very close range, and more based on a vague impression of mine, then on solid observations.
Not necessarily. Other people have testified before you that (modest) use of CrO, does not seem to undo the properties of a good Coticule edge. But it's never been really confirmed by an elaborate series of blinded tests.
What I can guarantee you, is that if you really got to the limit of what these Coticules can do, that you won't care to use CrO any longer. Most guys I know that reached that level of Coticule Mastery, took a while to realize that they really could do without the paste. I keep comparing it with learning how to ride a bike. Leaving the guide wheels off takes not only the proper skill do to without them, but also some self-confidence.
That is perfectly possible. Owners of a Les Latneuses (the one with the 2 Coticule sides) do this all the time. They often start on the creamy side and finish on the hybrid side. But you can do this with any combination of Coticules.