1. In 1944, USAAF suffered horrible losses over the skies of Europe, if I am not wrong, MIA/KIA were over 50%. USAAF struggled to find enough airmen to fill the losses. Yugoslav Embassy in Washington, DC informed U.S. Government that almost 600 U.S. and British airmen were saved and hidden in the mountain villages in Serbia and asked for their evacuation. Germans were looking for them and if found, it would be death sentence for the villagers hiding them and moving them from one village to another. U.S. Governent refused and declined to get MIA flyboys back from Serbia. The question is - WHY?
2. Preparation for the rescue mission was the private initiative of several OSS mentioned in the OP. They had to jump through the hoops and cut through the red tape. The question is WHY?
3. When rescue mission finally started, evac was assigned to Tuskagee airmen who did not have a proper training for such treacherous mission. As if someone within USAAF hoped they will fail. Again,the question is WHY?
4. When the war has ended and flyboys were home, they were given hard time to get this story known. And this was the biggest rescue mission of WWII. Numerous movies were made about every other WWII mission, even real failures such A Bridge too Far or fictitious events, yet, no one made a movie about Halyard Mission. The question is WHY?
5. President Truman awarded Legion of Merit
to Gen. Mihailovich in a secret ceremony in March 1948. The question is Why it was a secret?
I believ we owe the answers to all heroes who fought in WWII even if we have to wait a quarter of century to get still classified documents unsealed.