Dead human bones. Sorry, should have specified.
The shield blocks anything end everything, but I guess that some temperature (i.e. heat and cold) would get through. Just not enough to incapacitate him.
The shields are almost entirely limited to Phalanx himself. It can cover about a 2-10 feet dome around him. He can allow people through if he wants. More can get through depending on how large the shield is.
If he ‘Gifts’ the shield, it’s going to be a lot weaker, and it will only be one-sided.
the shields themselves have no mass whatsoever, and things will stick to them.