The original changes to Medinah No. 3 were not made because of Harry Cooper's 63. They were already planned prior to that, but had not been implemented because of a lack of finances.
Bendelow's original design was routed around land which the club's four founders kept to themselves, financing the purchase by skimming membership fees.
Once the membership found out, they sued the founders, who eventually got to keep the money (they made a killing), but handed the land back and were drummed out of the club. Bendelow, by August 1929, had drawn up, presented to the board and had approved the plans for the No. 3 that we eventually came to know through the mid-1980s. (The club has the blueprint for Medinah Forest, complete with the homesites and roads like Tripoli Drive, in its archives.)
Additionally, No. 3 really wasn't intended to be the ladies course. The original master plan for Medinah was for two 18-hole courses and a 9-hole ladies course on south of the clubhouse and north of Lake Kadijah and Medinah Creek.
Bendelow, seeing the memberships pour in as he designed No. 1 and No. 3, convinced the founders that a third 18-hole course was necessary, and while some early stories refer to that course as the ladies course (appending the concept of the 9 to the 18), Bendelow went about it as a third full-size course, working around the land the club didn't own. Even the original version, at 6,261 yards for the 1930 Medinah Open, was as long or longer than No. 2, which was designated the ladies course.