>>3. Good newer waterpump, no visible wear on it at all<<

That, i don't like. You should put a NEW one there.

>>4. New thermostat<<

Is it a VW OEM part 87deg? If yes, it will give 20% more heat.
Get a low temp 82 deg(or so) from any good parts dealer.

For those who says that the Engine will consume more fuel when running a
bit cooler i don't agree, my van run just below the light at normal
operathing temperature and i do 330 miles with one thank.

For the rest Jay and Andrew are perfectly right.