1) George B. McClellan (Peninsula Campaign / Seven Days Battles / Maryland Campaign)
* Edwin V. Sumner (temporary commander at the battle of Williamsburg)
* Fitz-John Porter (temporary commander at the battle of Malvern Hill)
2) Ambrose E. Burnside (Fredericksburg)
3) Joseph Hooker (Chancellorsville / part of Gettysburg Campaign)
* Darius N. Couch (temporary commander at the battle of Chancellorsville)
4) George G. Meade (Gettysburg Campaign / Bristoe Station + Mine Run / Overland Campaign / Petersburg + Appomattox Campaign)
* Winfield S. Hancock (temporary commander at Gettysburg, first day, until Slocum arrives)
* Henry W. Slocum (temporary commander at Gettysburg, first day, until Meade arrives)
* John G. Parke (temporary commander at the battle of Fort Stedman)
For the fifth permanent commander of the Army of the Potomac, neither John Pope nor Ulysses S. Grant are concerned (one commanded the Army of Virginia, the other had overall control of all forces in Virginia, namely the Army of the Potomac, the Army of the James and the Army of the Shenandoah) so I cannot tell who this guy could be.
Edit - Welcome to the trivia game, Gavriolo Sartorys. Hope you'll come back and play again.
Parke was intended to be the fifth correct answer, perhaps because he assumed temporary command on more than one occasion. I'm not sure all of the other names you mentioned should actually have been considered to be in command of the entire Army of the Potomac, even on a temporary basis, but I'm not going to try to determine military protocol at this point.
You get credit for a correct response to this question. For future reference, however, please note that as a general rule, if you give more answers than a question is asking for, you can lose credit if any one of those answers is incorrect.
hoosier