The thermostat will have to be removed to install the new water pump so it makes sense to replace it now. It is cheap so don't worry about cost, plus the shop would probably do it anyway.
I agree with rob on the coolant hose. The large upper coolant hose leaked after re-installation and I had a local shop replace it while they were doing a 07+ clutch install for me. So far I've only had the one hose leak. All of the other hoses were OK.