not very many as the free trade is mostly unpopulated and mostly filled with construction sites and no residential buildings. Maybe after more companies move their offices there you will see more users. But they will all only be able to access facebook only from their office so it is not like there will be that much new traffic to these sites
And when the companies move there, they'll just end up blocking facebook anyways to increase employee productivity!
That's the total number of users. This is very specific to the Free-Trade-Zone which, at present, is in the process of being populated by businesses. I don't know if residences will increase there, but this seems to be more of a calculated move to allow Chinese companies more freedom to work outside their borders and to allow external investment in China; not necessarily to allow ordinary Chinese citizens greater freedom to access information.