I'm assuming you've already completed your project. For future reference, the water pump on the 4.7 has a purge valve on the top that will displace coolant if the pump is malfunctioning.
To find out if it is malfunctioning, pressure check your coolant system (you can borrow the tools from AZ or Advance), wait a few minutes, look for coolant on the top of your water pump (about 1-2 o'clock).
I'd replace thermostat, thermostat gasket, and water pump gasket while you've got it off. That's so you don't have to drain the coolant again. It's also recommended you replace the fan clutch because they both have the same service life, and you've got to take the fan assembly off to get to the water pump. (Water Pump should be $45-50, fan clutch is an additional $45-50).
I recently changed out my water pump and got a bad fan clutch from the store. So I'm with a new pump and old fan clutch. Because sometimes you've gota live a little.