Great assumption with the sound. That totally makes sense. So it sounds to me like its definitely the pump. I watched a video and read the mechanic manual to see how its done. It doesnt look to bad, Id just need to get replacement gaskets for everything.It's actually not as hard as you would think. Basically just remove the exhaust, and drop the oil pan. Then its right there to get too. Just have to un hook all the pipes from the outside and then unbolt it from the bottom of the engine. Its not fun to do, and kind of annoying, but really not terrible. The water pump/oil pump unit is about $200 new. Or if your confident with it, you can take it apart and just replace the parts that need replacing. It's sometimes just easier to get a whole new unit.
And you know, I just thought about this. As you said the engine got louder with more ticking/tapping sounds. Well if the water pump isn't working, then your oil pump probably isn't doing much good either causing a lack of lubrication, which could be the cause of your noise. They are both the same unit and work off the same gear and shaft.
You will also need all the gaskets and seals and o-rings. So like the oil pan gasket, the o-rings for the weep hole tube, then all the pipes that go into the pump.
And just because its easier than the water pump, do you think it could potentially be my thermostat staying closed?