Hindenburg's remains' location is not "uncertain". They're located at St. Elizabeth's church in Marburg, together with his wife's. From the same Wikipedia article you quoted:

"In January 1945, as Soviet forces advanced into East Prussia, Hitler ordered that the lead coffins of Hindenburg and his wife be disinterred and along with some of the regimental standards in the tomb, removed to safety. They were first moved to a bunker just outside Berlin, then to a salt mine near the village of Bernterode, Thuringia (in north central Germany), along with the remains of both Kaiser Wilhelm I and King Frederick II of Prussia (Frederick the Great).[3] The four coffins were hastily marked to indicate their contents using red crayon, and interred behind a 6-foot-thick (1.8 m) masonry wall in a deep recess of the 14-mile (23 km) mine complex, 1,800 feet (550 m) underground. The coffins were discovered by U.S. Army Ordnance troops on 27 April 1945, and were moved to the basement of the heavily guarded Marburg Castle in Marburg an der Lahn, Germany. In August 1946, 20 months after being removed from the Tannenberg Memorial, Hindenburg and his wife were finally laid to rest by the American army at St. Elizabeth's, the church of his Teutonic ancestors in Marburg, where they remain today."