Forrest:
Not sure where you are going with this.
Mr. Ross and Mr. Jones each built about 400 courses, many in year-round climate zones, so theirs would get played the most on an annual basis, I think. Of course Mr. Ross's courses have been there for 30-40 years longer than Mr. Jones' ... I am not sure if you intended to figure that in or not.
Of my own limited work, the irony is that the most-played course would certainly be a lesser-known one, Heathland at The Legends, which used to play 50,000+ rounds per year. (I am not sure if the numbers in Myrtle Beach have held up of late.) After that, my most-played courses from one year to the next are probably Pacific Dunes and The Rawls Course. Sadly, some of my best work is some of the least-played, due to financial problems or short seasons (St. Andrews Beach and Cape Kidnappers and Ballyneal among them).
Based on that, I would guess that an architect in Florida or California would be near the top of the "average rounds played per course" listing you are looking for in your second question.