I am presuming this is to Capt. Mercer. OK, that does not mean that Porter was given any other orders than those that Lincoln signed with Seward present or any documents that were not presented to Lincoln by Seward on this issue.
If you have any other sources, I would willingly like to read them. So far you have not demonstrated that a special set of “Secret Orders” to Porter, to start a war at Pensacola was written by Lincoln.
We do not have a copy of Porter's orders. We have a copy of Mercer's orders relieving him of command, and placing a Lieutenant in charge of a major war vessel. (A Lieutenant is two ranks below a captain in the military ranking system of that time.)
For some reason, Porter never chose to release the text of his orders, but he was quite verbose about all the other things he did. He did show them to the harbor master, if I recall properly, but we can only judge what is in them based on how he proceeded to carry them out.
Can you think of any particularly good reason why he would sail the ship deep into the Atlantic away from normal shipping and then work so very hard to disguise the ship as something else? And then sail it all the way to Florida under a British flag?
Why would he do that? What possible purpose could he have in going out of his way to make sure nobody saw the Powhatan going to Florida?
And why would he immediately try to attack the Confederate shore positions upon arrival, and only be dissuaded by Meigs placing his ship in the path of the Powhatan. Porter even says he thought seriously of ramming Meigs ship to prevent it from interfering with his mission.
What mission was so important that he would consider ramming another US Navy ship to get at the Confederates?