And what gave South Carolina the authority to order federal troops from a federal facility?
...some blow-hard Fed capt/general occupies the fort...
A fort under Major Anderson's command, and which he moved to in the face of real threats from the South Carolina mob/militia.
...Fed. gov’t attempts to reinforce said capt/general...
Since the option was being starved into surrender then why are you surprised the federal government tried to resupply?
...SHTF time
Said poo being deliberately flung at the fan by the Confederacy then they are responsible for all the death and destruction that followed.
Their reclaimed sovereignty taken by force at Yorktown and later granted by George III in the Treaty of Paris of 1783, which was granted to the States severally and individually, South Carolina being specifically named and enumerated among the States thus created Sovereigns in law as well as fact.
Their resumption of their unified Sovereign powers by secession gave the Carolinians all the authority they needed to demand anything of anyone on their soil, under the terms of their own state constitution.
If you think a sovereign government does not have powers of taking in cases in dispute, just try your argument out on the Enforcement Division of the IRS and DoT.