There will be ~130 German generals added through an event at the start of the game.
You can choose if three of the generals will be added to Austria.
You can choose if Blomberg should be the only field marshal in 1936.
You can choose to have the military advisors as generals as well.
(If you add the three generals Austria, however, it is very possible that at least one of them will be field marshal after the Anschluss of Austria. However, there is no way to prevent that).