On that spout, you can remove the plastic slip on mechanism. It will leave you with a female thread on the inside of the spout. You can then extend and solder a male adapter (in the proper length) to the existing copper nipple. The new spout can srew into the normal male adapter.
Any holes on your copper tubing can be soldered to plug them up. Be sure and silicone the existing hole on the wall where the nipple petrudes your wall