Bach was not fired in 1734 as a Thomaskantor. He remained the Position until 1750 besides him being a court composer for Elector August the Strong.
Johann Sebastian Bach is portrayed as a man who has issues with the City council. In real life Bach received high support from Leipzig's mayor Gottfried Lange.
In the Scene in which Elisabeth is taking the Christmas tree home, the Christmas song "Maria durch ein Dornwald ging" is played in the version that was first released in 1850. The movie is set in 1734.
While Christmas trees exist in 1734, they were not to be found in the homes of ordinary citizens but rather of rich People. In Christmas Trees were popularized in Germany only in mid 18th century.