First, didn't Porter go with Powhattan to Fort Pickens, not Sumter?
Second, "Lincoln's plan" originated with Doubleday -- it was effectively the Doubleday/Fox/Lincoln plan and it was simply to use the cover of darkness and small boats to resupply Fort Sumter from larger ships sitting off shore well out of Confederate gun range.
DiogenesLamp:"I believe the orders referred to 'resisted in any way.' "
Orders to Fox & others used the words "opposed" and "resistance" without other modifiers like "in any way".
Regardless, no orders told any Union commanders to attack or assault Confederates in Charleston harbor, only to protect the Union boats delivering supplies to Fort Sumter.
Yes he did, and under secret orders directly from Lincoln which deliberately bypassed the Navy chain of command. Porter wrote about the Sumter expedition in his memoirs as if to excuse himself for taking this crucial ship away from the Sumter expedition.
Orders to Fox & others used the words "opposed" and "resistance" without other modifiers like "in any way".
Close enough.
"If you are opposed in this, you are directed to report the fact to the senior naval officer of the harbor, who will be instructed by the Secretary of the Navy to use his entire force to open a passage, when you will, if possible, effect an entrance, and place both the troops and supplies on Fort Sumter."