It reminds me of the power of delving into the "banished histories" of projects that Judith Tendler used to talk about to draw lessons about how something actually worked out and unearth the often hidden processes that contributed to success over time even in the face of apparent failure originally. I was most struck however by the third and fourth points you made -- about mixed use outcomes and the presence of land for light manufacturing/industry and services -- something that is missing in many current projects -- and yet is so crucial to providing jobs in proximity to where people live. I was curious whether this was envisaged in the original design of the settlements or was it something that emerged over time as the inhabitants lived their lives (as happens in so many informal settlements). Did the city then zone these in as mixed use areas? Am curious how the state - or at least the officials on the ground handled this, and whether there was contestation or 'mutual adjustment' over time. An ethnographic look into that process around land use, as well as how things turned out for the original owners or others as plots changed hands (or not) would be fascinating.
Also, the vibrancy that comes through so clearly in your narrative stands is sharp contrast to other housing developments and relocations in Chennai itself that have not (yet) turned out so well. Kannagi Nagar is one such example of a place that is struggling despite banks of brand new apartments (and relatively low rent) that residents can't want to get out of. When I visited that neighborhood a few years ago it was miles away from jobs, schools, affordable (public) hospitals or other basic amenities including reliable transportation. A sea of multistoried homes surrounded by calf-deep water and slush that the residents said were fonts of "nothing but disease."
So this model that you describe and the lessons that you draw from it are especially powerful today for what to do make current investments more viable. Thank you for this wonderful research!