Proposed Invasion of Charleston harbor by the North

Southerners believed that any Federal presence in the new CSA was an invasion of its territory. Rightly or wrongly that is what they believed. History and SCOTUS has proved their belief to be wrong but that will not stop the Neo Confederates from rallying behind it almost a century and a half later.

Someone please explain what the highlighted part means. It seems Lincoln is writing in cypher.

WASHINGTON, May 1st, 1861.
Capt. G.V. Fox:
My Dear Sir, I sincerely regret that the failure of the late attempt to provision Fort Sumter should be the source of any annoyance to you. The practicability of your plan was not, in fact, brought to a test. By reason of a gale, well known in advance to be possible, and not improbable, the tugs, an essential part of the plan, never reached the ground ; while, by an accident, for which you were in nowise responsible, and possibly I, to some extent, was, you were deprived of a war-vessel, with her men, which you deemed of great importance to the enterprise.
I most cheerfully and truthfully declare that the failure of the undertaking has not lowered you a particle, while the qualities you developed in the effort have greatly heightened you in my estimation. For a daring and dangerous enterprise of a similar character, you would, to-day, be the man of all my acquaintances whom I would select. You and I both anticipated that the cause of the country would be advanced by making the attempt to provision Fort Sumter, even if it should fail ; and it is no small consolation now to feel that our anticipation is justified by the result.
Very truly your friend, A. LINCOLN.

The invasion force was to be about 500 men. 300 were onboard the Powhatan that was mistakenly sent to reinforce Ft. Pickens where they were'nt needed. Why is the 200 number repeated over and over.

Another question, why was it made public that the garrison of Fort Sumter was starving and that they had food to last only until April 15th? They were allowed to buy food from Charleston until April 7th.

Was this some kind of propaganda to influence the Northern and world opinion that the evil southerners were starving the poor garrison to death?

It was indeed a brilliant move to sway public opinion in the north. It was for Lincolns and sort of "heads I win, tails you lose". Lincoln out-smarted Davis. causing Davis to open the war, which is why it was so easy to muster thousands of recruits to the US Army to put down the Rebellion.

So Lincoln wanted war and was willing to provoke the first shot to start it. I wouldn't call it brilliant, maybe sinister. His cabinet tried to persuade him to evacuate the fort because it would start a war.

There were Cannons positioed at Sumter, so I'd say that Davis was prepared to provoke the first shot. Lincoln just put the ball in davis's court. If Davis fired on Ships, which he did, and if he fired on Sumter, which he did, than American opinion would be in favor of Mr. Lincoln. If Davis let the ships with provisions through, It would have been a show of US strength in keeping a federal instillation, and thus maintaining the upper hand. Lincoln did NOT want war. You can find his letters all over the internet to that effect. But if war was inevitable, He was going to make **** sure that he was in a position to win it, and as quickly as possible and bring the Confed's back in to in the Union.

Wilber, you said the OR's don't mention reinforcements to Fort Sumter. Here is an example from the OR's.

Official Records of the Civil War
SERIES: I VOLUME: I CAMPAIGN: Charleston SERIAL: 001 PAGE: 0236

HEADQUARTERS OF THE ARMY, Washington, D. C., April 4, 1861.
Lieutenant Colonel HENRY L. SCOTT, A. D. C., New York:
SIR: This letter will be landed to you by Captain G. V. Fox, ex-officer of the Navy, and a gentleman of high standing, as well as possessed of extraordinary nautical ability. He is charged by high authority here with the command of an expedition, under cover of certain ships of war, whose object is to re-enforce Fort Sumter.
To embark with Captain Fox you will cause a detachment of recruits, say about two hundred, to be immediately organized at Fort Columbus, with a competent number of officers, arms, ammunition, and subsistence. A large surplus of the latter-indeed, as great as the vessels of the expedition can take-with other necessaries, will be needed for the augmented garrison of Fort Sumter.
The subsistence and other supplies should be assorted like those which were provided by you and Captain Ward of the Navy for a former expedition. Consult Captain Fox and Major Eaton on the subject, and give all necessary orders in my name to fit out the expedition, except that the hiring of vessels will be left to others.
Some fuel must be shipped. Oil, artillery implements, fuses, cordage, slow-march, mechanical levers, and gins, &c., should also be put on board.
Consult, also, if necessary, confidentially, Colonel Tompkins and Major Thornton.
Respectfully, yours,
WINFIELD SCOTT.

My hilite and there are more as I find them.

To warn Gov. Pickens not fire on a ship that was only trying to relieve hungry soldiers. Again, the ball was in Picken's court. Whether or not Pickens chose to allow these provisions would sway public sentiment.