Members of the Seward family, including Frederick, Augustus, William, Fanny, and possibly the servant, William Bell, outside of the Seward home post assassination.
Image Source: PictureHistory.com
Seward family outside the house post assassination
The History Behind Lincoln's Assassination
LincolnConspirators.com 
Where is Fanny?
This is the family’s Auburn, New York house after Seward’s tenure as Secretary of State. NOT the one he was attacked in.
The photo was taken at Seward’s home in Washington as noted in Walter Stahr’s Seward: Lincoln’s Indispensable Man. The link below shows the back of the house with its covered porch that Fanny called the “piazza,” which is another name for a veranda or a porch. The date of the image is thought to be 1857 when it was still owned by Minerva Rodgers and occupied by the Washington Club.
In the image, the house is on the lower right side facing Lafayette Square. It is the second house from the corner with the buildings attached in the back..
Fanny is not in the photo.
According to the Seward House Museum, Anna Seward is standing between a young woman and Anna’s husband Fred, Gus Seward is looking out the window, then Mrs. W. Martin and William Seward.
The Seward House didn’t identify the people on the right side of the photo but they are probably the servants. The older woman is most likely the housekeeper Margaret Coleman and the younger man at the far right is probably William H. Bell.
Here is the link to “Isometrical view of the Presidents House, the surrounding public buildings, and private residences : [Washington D.C.].”
https://www.loc.gov/resource/g3852w.ct002293/?r=0.573,0.099,0.645,0.236,0