Baltic also carried 4 months worth of food for the garrison at Sumter.
Again, Davis would have opened up fire on Sumter regardless of what ships were sent to resupply the fort. He had already made the decision, preventing the resupply of Sumter, even if it meant war, had to be done.
Again, it was a heavily armed flotilla. Had Lincoln not gotten his war started in Charleston, he would have in Pensacola or some other Southern port. Had the Confederates not opened fire, Lincoln would have simply invaded all their ports without resistance.