That's an interesting evolution for DuPont - for some reason Ross did not list that course on his list of designs (around 1930). Any thoughts why he would not list it? Is it possible he incorporated some of Reid's nine-hole course?
My mistake - I forgot about the name change for Ocean City. That is another course with an interesting history. the project was anounced in 1915, but whatever reason the course was not completed unitl 1923.
In southern California Caves Landing at Pisbo Beach (near San Luis O) was designed by JD Dunn and George Thomas, and I believe MacKenzie consulting. Dunn compared it to Muirfield.
Another one is Dana Point, which was supposedly a spectacular site. One article had MacKenzie and Hunter doing it, another Max Behr and Billy Behr (which would have been an interesting collaboration). With Berh and MacKenzie being friends I'm surprised they never worked together.