Short answers, pulled from the story.
Maria Anna Mozart entered the world on the 30th of July 1751 and became known as Nannerl. Her father Leopold began teaching her to play the harpsichord when she was seven years old.
Society viewed professional positions open to women as limited to singing rather than keyboard performance. By 1768, she essentially ended her public career as a touring musician because her brother continued to tour with Leopold while Marianne stayed at home in Salzburg.
Marianne married magistrate Johann Baptist Franz Freiherr von Berchtold zu Sonnenburg on the 23rd of August 1784 and settled in St. Gilgen. This village is located about twenty-nine kilometers east of Salzburg and was described by her as a wilderness.
Wolfgang sent her works he had composed including the Prelude and Fugue in C from 1782. She received copies of his piano concertos up to number twenty-one in St. Gilgen until 1785.
Her career as a part-time piano teacher began in Salzburg in 1772 and lasted through the last years of her unmarried state. She taught several young women of Salzburg including daughters of the aristocracy like Count Lodron and members of the middle class.