Change the gasket, the honda bond is not a must, so as long the surface is clean on the valve cover and the head you'll be good. As far as tightening the nuts, I don't have the specs. However they break easy if they are over turned, so here...when it gets tight, go one more 1/2 turn and stop, that is good. As far as the order you tighten them, caddy corner just like when putting a wheel on your car. Plug gaskets/donuts should be fine, those don't have to be changed that often, they usually last longer than the car. If yours are damaged than yes, other wise if they look ok, most likely they are.