a) The city center is not an expensive area, you can find a good apartment of 2 bedroom for $800 USD
b) There are plenty of international schools, with school fees for around $700 USD a month ( some are more expensive, some are cheaper but I guess thats the average)
c) Usually, my family expense for groceries (we are 4) are around 250USD, and public services for an middle-upper social class are around 300 USD ( water + energy + gas + internet)
d) A maid commly works for $15USD a 8-hour day