As far as the architectural history of the East course, I used to have David Goddard's detailed history of the course/club but I let someone borrow it who let someone else borrow it so whatever I have is largely from that now second-hand source.
My understanding is that the East included a number of original green sites from the club's original 18 holes opened by Willie Park, Jr. and Adrian Larkin in 1899. In 1915 Park's brother John with Larkin made additional enhancements. It's rumored that Seth Raynor made significant enhancements to the overall Maidstone property and/or created an entire new East course around 1921 but no physical evidence of that has been uncovered. In 1924 Willie and John Park created a new property plan that created two 18 hole courses that was largely implemented by brother John between then and 1930.
During WWII the club sold off land that included 7 holes of the East. Eventually, two holes were combined to create today's 2nd hole, another hole was abandoned and the remainder constitute today's course.
Any corrections or additional information is welcomed, thanks.