The taller woman standing against the front door frame could be Louisa Sprague. The assorted little girls would probably be Annie, Harriet, and Estelle Sprague. If this picture was taken while Rosetta lived with her parents from 1876 to about 1878, Then Annie was between 11 and 13. Harriet was 10 to 12, and Estelle was 6 to 8. They had a sister, Alice, between Harriet and Estelle, but she had died in 1875. They also had a little sister, Fredericka, and a little brother, Herbert, ages 4 to 6 and 1 to 3 respectively. If this was taken in 1877, then the other man was the dishonored Nathan, fresh from jail in New York.
This configuration of the household was not uncommon. There was a reason Douglass kept adding onto the house. In fact, take a look at the architecture. His granddaughter, Fredericka, later described the house as "really two connecting houses. Communicating doors were cut through the halls both up and down stairs, thus enabling the family to have desired ample space." According to her, subsequent owners blocked up the connecting doorways and the one house became two.When he moved to Cedar Hill, which was bigger than this house, he enlarged it, as well.
The front parlor lay beyond the bay window. Fredericka said that Douglass, despite having another room dedicated to his study, sometimes annexed this room, as well. You can read Fredericka's full account of her grandfather in her reminiscences located in the Frederick Douglass Collection in the Moorland-Spingarn Center at Howard University. They are quite charming.