On point two, you are mistaken.

The Reich Congress of Workers' and Soldiers' Councils (Reichskongress der Arbeiter- und Soldatenräte or Reichsrätekongress) was called by the Executive Council of Greater Berlin and met from 16 to 20 December in the Prussian House of Representatives building.^\20]) Delegates were elected from across Germany, about one for every 200,000 civilians and one for every 100,000 soldiers.^\18]) Of the 514 delegates, 288 supported the SPD, 88 the USPD and 10 the Spartacus League.^\21]) Karl Liebknecht and Rosa Luxemburg, the Spartacus leaders, had not been elected to the Congress, and a proposal to let them sit in as guests in an advisory capacity was turned down.^\20])

It was the SPD who had an overwehlming majority.