Short answers, pulled from the story.
General Orders 11, issued by Hunter in May 1862, declared all enslaved people in Georgia, South Carolina, and Florida permanently free on the grounds that slavery and martial law could not coexist. President Lincoln rescinded it on the 19th of May, 1862, because he feared its political effects on the border states, whose leaders were advocating gradual emancipation with compensation for slave owners.
Hunter formed the 1st South Carolina (African Descent), the first such regiment in the Union Army. He enlisted formerly enslaved men from occupied districts in South Carolina without permission from the War Department, was initially ordered to disband the regiment, but eventually received congressional approval.
Hunter burned the Virginia Military Institute on the 11th of June, 1864, in retaliation for the institution having sent cadets to fight against Union forces at the Battle of New Market. His scorched earth campaign in the Shenandoah Valley was carried out on orders from Lieutenant General Ulysses S. Grant.
Hunter served as president of the military commission that tried the conspirators in Abraham Lincoln's assassination, from the 8th of May to the 15th of July, 1865. He had also served in the honor guard at Lincoln's funeral and accompanied the president's body back to Springfield.
Hunter began a correspondence with Lincoln in 1860 while stationed at Fort Leavenworth, Kansas, emphasizing his anti-slavery views. After Lincoln won the presidency, he invited Hunter to ride on his inaugural train in February 1861 from Springfield, Illinois, to Washington, D.C. During that journey, Hunter suffered a dislocated collarbone when a crowd pressed against the train in Buffalo.
David Hunter died on the 2nd of February, 1886, in Washington, D.C. He is buried at the Princeton Cemetery in Princeton, New Jersey.