Yes, Circular Quay is closer. Doesn't much matter which station you get off at, though; - there may be some climbing uphill. And I agree with Dee; there probably won't be much time for Library studies, with that many of us getting together (look out, Sydney!).
Neil, the Library was my initial suggestion as a meeting place, basically because my various-degree-cousins and I have met there in the past. However, since finding a lunch venue near there was nigh on impossible ... the Australian Heritage Hotel sounds like it might be a better option.