The new generation dry sump pumps are very capable of pulling over 18"s of vacuum. Oil is still "spraying" (pressurized) out of all of the normal areas and at speeds high enough to oil the cylinder walls , camshaft , etc. no problem. The vacuum actually "pulls" oil out of the crank and slightly lowers oil pressure. Oil is still flowing. I haven't ever seen a piston scuff caused by crankcase vacuum. In my experience , the pins ( unless pressure fed through the rod itself) receive splash oiling or non pressurized oil from the oil ring groove and high vacuum reduces the amount of oil they get. The DLC ( Diamond Like Carbon) coating provides a VERY hard surface that is also very slippery so it survives is a low oil , high load situation. At 3 to 5 times the cost of a non coated pin , they are pricey but since they don't wear on the surface , they can be used over and over and over. The cycle life ( amount of times it can flex before it yields) is far beyond the wear factor of the cylinder walls so "long term" use actually makes them cost effective.
Randy