We learn that one hundred and fifty able-bodied free colored men of Charleston offered their services gratuitously to the Governor to hasten forward the important work of throwing up redoubts wherever needed along our coasts. [Charleston Mercury, January 3, 1861]
A gentleman from Charleston says that everything there betokens active preparations for fight. The thousand negroes busy building batteries, so far from inclining to resurrection, were grinning from ear to ear at the prospect of shooting the Yankees. [Washington dispatch to the Evening Post, date not provided in the Congressional Globe]
We learn that about seventy of the most respectable free negroes in this city have enrolled themselves, and design tendering their services to the Governor to act in whatever capacity may be assigned them in defense of the State. Three cheers for the patriotic free negroes of Lynchburg. [Republican, Lynchburg, Virginia, April, 1861]
The negroes in all this section of the country, slave and free, are as loyal as could be desired. They freely proffer their services to the State and zealously contend for the privilege of being allowed to work on the batteries. Yesterday General Gwynn declined the services of three hundred from Hampton who solicited employment on the batteries, and twice and thrice that number could be obtained in this vicinity in a single day, if it was thought advisable to accept them. Indeed the entire fortifications of this harbor might be constructed by the voluntary labor of negroes, who would claim no higher reward than the privilege of being allowed to contribute their share toward the defense of the State and the protection of their masters and mistresses, who had always extended a sheltering hand over them. [Petersburg, Virginia Express, dated at Norfolk, April 23, 1861]
And in all your examples that service was, without exception, declined by the government. Government sanction of free blacks in the military was not granted until 1862 (for musicians only) or 1864 (for service positions only) or March 1865 (when blacks were accepted for combat positions.) Unofficially blacks, free and slave, were brought along with the army as cooks, servants, laborers, and the like from the very first.