Here's a list of some of the people that met with General Sikorski, or accompanied him, on his visits to the USA in April 1941. I gathered this info from old newspaper articles. Perhaps some of them appear in the photos.
Chicago: Jan Ciechanowski (Polish Ambassador to the U.S.), Stanley Mikolajczyk (President of Polish Parliament), Sylvian Strakacz (minister plenipotentiary), Major Victor Cazalet (British parliamentary member and liaison), Rear Admiral John Downes, General Charles H. Bonesteel, Lewis Bernays (British consul general), Dr. Karol Ripa (Polish consul general), Chauncy McCormick, Gov. Dwight Green, Donald F. McPherson (head of Chicago Council on Foreign Relations), Ignace Jan Paderewski (pianist, president of the National Council of Poland), F.X. Swietlik (president of Polish-American Council, dean of Marquette University law school), Dr. Jan Papanek (representative of the Czecho-Slovak government in exile in Great Britain), Archbishop Samuel A. Stritch (Catholic Archdiocese of Chicago), Casmir Midowicz (vice president of Polish-American council)
Washington D.C.: President Roosevelt, Lord Halifax, Cordell Hull (Secretary of State), Henry Stimson (Secretary of War), Harry Hopkins (in command of the Lend-Lease program)
Fort Meade: Colonel Kitkiewicz (deputy Chief of Staff of Polish forces in exile), Captain Zamoyski (General's aide), Lieutenant Colonel J.S. Winslow (US Army General Staff Corps), Colonel Gilbert M. Allen (Fort Meade post commander)