No, the Revenue Service was tasked with protecting the ports and coastal waterways of the United States. They are the precursor to the modern Coast Guard, but were under the command of the Secretary of the Navy. They were not tasked with collecting duties, that was the Treasury Department.
The de facto situation of secession says otherwise.
De facto my foot. The confederacy was not an independent nation in 1861 and was never recognized as such by any country at any time. Charleston was a city in the United States.
Not in this situation. The Lincoln specifically sent the Harriet Lane there along with other ships to participate in military activities involving Fort Sumter.
De facto my foot.
Barring a previous amputation of your foot, de facto indeed.
The confederacy was not an independent nation in 1861
It declared its independence, identified its own boundaries, set up its own government, and operated under that government without control of another. That is de facto independence.
and was never recognized as such by any country at any time.
That is not so. It was recognized by the Vatican, which by precedent is the oldest and original form of diplomatically recognizing a nation's legitimacy in the world.