How did the film portray Hitler and other key figures like Goebbels, Himmler, Speer, and Fegelein? According to the film to what extent did Hitler believe in the Nazi propaganda (Genetics, eugenics, and ethnic cleansing)? Was he just using the propaganda as a means to control the German people? Many critics say this film humanizes Hitler too much, creating a sense of sympathy for him. Do you agree?
Much more could be said, especially because I found information only about a few of your questions, but in the interim, you might like these links to previous discussions.
For the title question, "How historically accurate is the film Downfall?" has answers by /u/kaisermatias and /u/KatsumotoKurier .
For the last question, about humanizing Hitler, some opinions were given here , with opinions by /u/JimmyRecard and createanewfolder.