Did you pack the pump when you installed it? Assembly lube or petroleum jelly works. If not, I wonder if the scaring was from a dry start up.

I also wonder how flat the cover was. Was everything torqued equally?

As for the valves and head, i would not worry about it. The light white was probably from heat or lean. I doubt either was really a factor. What do the valve seats look like? Are the contact areas on the valves and head all about the same? As far as lapping valves, I would not touch it unless there seems to be some other problem. That head is pretty much fresh.

As for the block, while that wear on the pump is worry some, it would not make enough sound to explain what you heard over the sound of a running engine. The crank really turns over OK like?

Hmmmm, what did the pilot bearing look like? Can you spin the cam? Is there any debris on top of the head?

Just some ideas.

Michael