1. Is it necessary remove the "Water Pump Shaft"?

2. What are the benifits if it's done or not?

3. Is that silver cap thing that comes with the CSI water pump the "Freeze Plug"?

4. Are any gaskets or sealers needed for the water pump or the complete waterpump assembly when being put back onto the engine?

Thanks...

 

I removed it on mine, not very hard at all, I just took a punch through the lifter valley and punched it out towards the front of the engine.

I would assume a little less drag on the camshaft gear.

Yes that is the freeze plug that goes in.

Use some black RTV sealant around where the water pump mounts to the water pump housing, just place the water pump on there, wait 24 hours, then tighten it down. It will act like an o ring.