The "Neukunstgruppe" (New Art Group) was found in 1909, not 1910 as in the movie. It's the same year as Schiele left art academy.
The famous painting "Death and Girl" was painted after Egon Schiele's wedding to Edith Harms, not before, as shown in the movie.
During several closeups it can be seen that Noah Saavedra (Egon) and Valerie Pachner (Wally) are wearing contact lenses. The distinctive transparent rings around the irises are clearly showing.
In 1914 Egon and his female partners are watching Der Hirt von Maria Schnee (1920) in the movie theater and mention Moa Mandu, who appears in it. The movie was filmed in 1919 and released one year later.
While being in Krumau in 1911 the gang is listening to "The Nightmare" by Elgar's Creole Orchestra. The tune was recorded in 1926.
When suggesting Mao's new stage name "Moa Mandu" Dom mentions that Mandu is a river in Sierra Leone. In real life is a river in South East Brazil.