Sure they did. They had reporters on the field who saw the battles and their aftermaths first hand.
especially the existence of those phantom black Confderates whom neo-Confederates love to conjure up.
You mean the ones that are documented in the official muster roles, pension records, and even the US Government's War of the Rebellion set of records from the war?
Your relying one ill-informed source to corroborate another is highly illogical.
Demonstrate that either Greeley or Douglass was ill-informed. Or is that simply another of your infamous and frequent gratuitous assertions?