Answer: What is the difference between a "Cold War" and a "hot war?" A "Cold War" is one in which there is no physical battles but instead tension between two nations (political, economic, etc.). Therefore, the opposite (a "Hot War") would entail actual fighting.
Answer: The Freedmen's Bureau, born out of abolitionist concern for freed slaves, was headed by “Union General Oliver O. Howard” for the entire seven years of its existence.
The uprising that resulted in the creation of repressive laws that restricted enslaved people would be The Slave rebellion led by Nat Turner in August 1831 I believe