I didn't access those links until now, but I had seen them before. I have stated that some argue that the Nashville was fired on by the Harriet Lane on the night of the 11th, and others say it was fired on during the 12th. The last link of post 1725 suggests that the firing on the Nashville happened after 3 AM, but it is not conclusive in that regard since in that communication Fox mostly talks about the ships in his convoy. I have posted before elsewhere on the seizure of the ice schooner Fox refers to.
However, the following 1865 document by Fox suggests the Nashville did not arrive until sometime during the 12th. [Link]
I don't know if you saw my post to Greetings From Boston Man, but I found an article in the Southwestern Historical Quarterly July 1935 issue written by Lt. Cmdr. David P. Marvin, USCG, ret'd., a faculty member at the Coast Guard Academy. In that article he says:
Lying at the rendezvous off the bar, Captain Faunce observed a steamer approaching, and as she had no colors flying, the Lane fired a 32-pound shot from the bow gun, as an order to halt. This shot, at 11:20 a. m., April 12, 1861, was the first of the conflict to be fired from the deck of a Federal vessel.The stranger proved to be a merchant steamer from New York, the Nashville, with passengers and freight, and was allowed to pro- ceed to Charleston; she was later taken over by the Confederate government, used as a cruiser, then as a ram, and was lost in battle.