To me, white plugs are usually a sign of burning coolant... But... you say it sits alot and it's cold... Could be condensation in the crankcase. Change your oil and try it again.
Another thing that can happen if you do a head gasket is forgetting to drain the oil pan AGAIN after you pull the head off, as quite a bit of coolant can run down.
The temp getting hot is somewhat strange, but I would change your oil and see if it happens again. Maybe your thermostat got stuck, or your "new" waterpump ate it.
