Short answers, pulled from the story.
The German Student Union emerged in 1919 as a merger of general student committees from all German universities. This new body included institutions across Danzig, Austria and former German universities in Czechoslovakia.
Peter van Aubel led the organization from 1920 to 1921 while representing Katholische Freie Vereinigung Cologne. He represented the group based in Göttingen before Franz Holzwarth took over for the following term.
Members of the German Student Union launched an organized attack on the Institute of Sex Research located within Berlin's Tiergarten area. Workers hauled out the library and archives into the streets of Opernplatz where they burned approximately 20,000 books and journals along with 5,000 images.
Gustav Adolf Scheel served as chairman from February 1936 until the organization was banned in 1945. He held the title of Reichsstudentenführer leader of both DSt and NSDStB simultaneously.
The National Socialist German Students League gained dominance over the union starting in 1931. Gerhard Krüger assumed leadership from 1931 to 1933 while holding positions with both NSDStB and Burschenschaft Arminia Greifswald im ADB.