Mark,
The records I have from Olympia Fields give Watson sole credit for Course 2, and he and Bendelow are credited with co-designing Course 3. This of course may not be accurate, so I'd be interested in where your info came from. At some point, Course 3 had some wild bunkering, but I don't know if either of them did it, or Jack Daray or even Willie Park Jr. did, as he is listed in board minutes from 1920 or 1921 as being hired to consult on Courses 1, 2, and 3.
The 18th hole from Course 2 is now No. 9 on the South Course, and retains the same green contours it had in 1923, though a chocolate drop from around the green is gone. For good or ill, it is still referred to as the Willie Watson hole.