Updated thanks to some help from Stefan and JD :) and my own continued detective work. Thanks.
Sheridan’s Staff – June 1864
Top Row Standing on Porch:
Capt. Joseph O’Keeffe, Capt. Michael V. Sheridan, Lt. Col. Frederick Newhall, Unknown, Maj. George “Sandy” Forsyth, Capt. Louis Carpenter, Unknown, Capt. James F. Wade
Standing on Top Step:
Might this be Col. C. R. Smith of the 6th PA Cav? Sheridan had him on his staff.
Unknown, Capt. Thomas W. C. Moore, Col. James “Tony” Forsyth, Gen. Sheridan
All officers to the right of Sheridan are unknown at this time. Any help you can provide in identifying any of these officers is greatly appreciated. It is interesting to try and figure out and one can go back and forth on id’s. For example, Sheridan’s brother Michael could be one of two men. If you look at a picture of MVS twenty years later, the second man from the left in top row seems to be the proper id. However, it was said that he looked just like Phil. Looking at General S’s photograph as a lieutenant in the Regular Army in the 1850’s, the third man from left on the top row is a convincing choice.