The grease doesn't hurt anything. It just keeps you from destroying the
gasket if you DO have to take the head off again. Many gaskets are impregnated
with what becomes a thermoset adhesive so that it takes a major scraping job
to get the remains of it off the head and block.

Retorquing is a GOOD idea and should be done sometime after the engine has
been run long enough to get up to operating temperature and stay there a while.
Some of the components relax, the gasket may compress a little more, etc so
retorquing guarantees that you have the required clamping force between the
head and the block. You don't have to go through the whole sequence, just
break each bolt loose and then retorque to 65 ft-lbs in the original spiral
sequence starting at the center. You will have to remove the rocker shaft
to do this but will probably not have to do much in the way of valve adjustment.
It IS, however, good practice, to check valve lash at that time and adjust if
necessary.
--
George Downs Bartlesville, Heart of the USA!