Here's a list of all of the courses noted in the article.
Everglades CC - Seth Raynor course later renovated by Langford and Moreau. Robertson noted as professional in the 1923 Annual Guide (the first guide the course appears in) and noted in the press playing in the inaugural match at the course in 1920. He may have helped construct the course
Aviation CC lka Lochhaven CC lka Green Lake CC - April 1921 Golf Illustrated notes the first 18 hole course was laid out by Herbert Strong. A 9 hole course was added later. It is possible that Robertson was splitting time between Aviation and Everglades in the early 1920's. It is also possible that his involvement here was with the 9 holes that were added later.
Glen Oaks - June 25, 1929 Detroit Free Press notes Willie Robertson retained to lay out a 9 hole course which was completed in 1926 with full 18 opening in 1927 and now measuring 6,240 yards.
Lancaster Hills - The only record I have of this course is the 1940 Detroit Free Press article with a map you recently forwarded.
Beverly Hills - The only record I have of this course is the 1940 Detroit Free Press article with a map you recently forwarded.
Holly Valley - I have no record of a course by this name in Michigan.
Twin Beach - Located in West Bloomfield, course dates to 1930.
Twin Lakes - Located in Pontiac. 1941 Oakland County Guide notes a 9 hole 3,270 yard course.
Houghton Lake - There was a Pine View Highlands GC in Houghton Lake that dates to 1934. (As an aside, the pro/greenkeeper here had one of my favorite names in the business, Harry Flora.)
Lost Lake Woods - I have no record of a course by this name in Michigan.
It is clear that Robertson did design and construction work on at least one of these courses. It is entirely possible that at many of these he did both.