More freed slaves were put to work as manual laborers than went into the army. They had a choice between the two or working their old jobs on the plantation for wages.
That article is pretty reliable picture too. The contraband camps were crowded and disease ridden, so much like early army recruits died from diseases, the freedmen died when congregated together. Many worked plantations for the government for wages too.
Most success was at the local level. John Eaton, a former Ohio school superintendent, was one of the heroes of this story in the Mississippi Valley. The Quakers, abolitionists and men like John Eaton did great work but most indicated they were frustrated that there was so little they could do or they were hampered by circumstances. The government plantations also had problems with guerillas as the armies moved on and many were killed or taken to Texas and re-enslaved. Some freedmen even tried farming closer to Confederate occupied territories and the guerillas were an even bigger problem for them.
The Federal government support of the freedmen was abysmal. Care for the Freedman was split between Treasury and War. This did not make for efficient care but rather easy finger pointing between Chase and Stanton. I'm not an advocate of big government but there is a case that a cabinet level position should have been created to solve the problem, at least temporarily. As it was, an attempt to create the Freedman's Bureau during the war was voted down by Congress, so the Freedman's Bureau was three years too late when it was finally created in 1866. It was not a happy chapter in US History as Lincoln and the Feds were too busy fighting the war and did not make or have time for solving the freedman problem.