... There were approximately 450,000 black slaves in the 1860 census residing in Northern states that did not succeed. The Emancipation Proclamation did not apply to them.
Strangely, the four states you are talking about -- Delaware, Maryland, Kentucky, Missouri -- were considered part of "the South" by the people who formed the Confederacy. They expected all four to join with them in the "Winter of Secession" and sent envoys to them to try to subvert their loyalty. They even tried to claim Kentucky and Missouri had seceded and joined the Confederacy during the Civil War. Yet here you are claiming they were "Northern states".
Legally, Lincoln had no authority that would have allowed the Emancipation Proclamation to apply to those four states because they were not in rebellion against the United States of America. That is why they were not included in the Emancipation Proclamation. Lincoln did try working to get those states to emancipate their slaves -- particularly in Delaware, recruiting the largest slaveholder in the state to head the effort, but Delaware turned the offer down.