Interesting post...

Perhaps the salvage company or the Army (whomever owned the engines at the time) didn't try very hard to find a buyer. Latin American railroads were buying much older second-hand engines at the time. It is also a mystery that the D&RGW didn't want even a couple of them back. Perhaps the Government settled the 1942 requisition with the road by paying some cash. Another interesting but little-discussed policy of the US Armed Forces after WWII... Disposing or otherwise scrapping war materiel, and not bringing it back to the States as war surplus. There was a fear that a massive infusion of war surplus into the American economy could hurt domestic manufacturers.
It is also perplexing why the WP&YR men did not like the class. They were well liked on the D&RGW. I heard they main rod counterweight climbed up on ice, derailing these engines. However, WP&Y #69 has large counterweights.