While the movie doesn't specifies when then first movie is set, it is clearly set around 1730. It is shown for King Frederic Wilhelm I to have 5 kids and Crown Prince Frederic, Princess Friederike (whom the king called "Fritzchen") and Priness Wilhelmine. However in real life he had 6 children who were alive, not including Wilhelmine, Friederike and Frederic, who were adults already.
When talking about the duchies Jülich and Berg king Friedrich Wilhelm said that if he gets these duchies the Prince of Wales gets his daughter Wilhelmine. However Jülich and Berg were not owned by the British crown. It was owned by the Elector of Pfalz-Bavaria.
King Friedrich Wilhelm I said from the beginning that he wants his son Friedrich to be imprisoned after his betrayal due to the escape attempt. However in real life he wanted him to be killed as well as Lieutenant von Katte. However after talking with Prince Leopold I of Anhalt-Dessau (who is not portrayed or mentioned in the movie) he decided to spare his life and leave him imprisoned.
The first meeting of King Friedrich Wilhelm I and Count Friedrich III to discuss his married with Princess Wilhelmine was in 1731, one year after Friedrich II's flee attempt and the death of Hans Hermann von Katte. In the movie it is the other way around.
While it is true that Friedrich II wanted to flee from his father he told it his friend Hans Hermann von Katte in Riesa, not in Potsam. Furthermore his escape attempt with Katte was to France, not to England. His attempt to England was after Kattes death with his henchman Peter Karl Christoph von Keith.
Both King Fredrich Wilhelm I as well as the future Friedrich II are addressed or mentioned as "King of Prussia". This title didn't exist until 1772 after King Friedrich II after he conquered Polish-Prussia, Ermsland and other Eastern regions that gave him ownership for "both Prussias". Until then the title was "King IN Prussia".
While it is true that king Friedrich Wilhelm I and his son, later king Friedrich II didn't go along and later declared peace, it happened in 1731-32, not shortly before his death in 1740. However until the king's death the connection between them was not very clear.
The tune that is played during the wedding between Prince Friedrich and Princess Elisabeth Christine von Braunschweig-Wolfenbüttel-Bevern is the Flute Concerto in G major by Johann Joachim Quantz. It was written around 1745 while the wedding took place in 1732.
In the scene, set in the 1730s, one of the King's sons is seen playing with unit block set. These didn't exist in the German regions until the second half of the 19th century.