Generally speaking...all that you mention in my opinion should be replaced...along with any oil seals that could leak that can be replaced without too much added labor. Also in some cases if the belt has a tensioner or idler pulley that can cause problems at a later date should be replaced for better long term preventive maintenace.
Timing belt, water pump, upper and lower idler, hydraulic tensioner, coolant, both drive belts.
We don't normally change the seals, but we do inspect them. If they are dry we leave them be.
Lastly, you may want to do the thermostat and thermostat gasket as a preventative measure as long as the coolant is drained out.
Hope that helps!
Eric Sevim - ASE Master Certified Technician
A+ Japanese Auto Repair - San Carlos CA 94070