The various stories Fanny Price writes are actually Jane Austen's Juvenilia, written when she was a teenager.
'Mansfield Park' was Jane Austen's most successful novel in her lifetime, earning her in excess of £300.
The instrument played by Julia and Maria Bertram is an armonica, invented by Benjamin Franklin in 1761.
The production company apparently left behind the flock of doves released at the end of Henry Crawford's fireworks display (filmed in Charlestown, Cornwall). For more than eight years after filming was completed, the birds survived thanks to the efforts of a local woman who feared they would perish, due to having to compete with gulls for food.