Short answers, pulled from the story.
Secretary of State William H. Seward proclaimed the measure ratified on the 18th of December 1865. This amendment abolished slavery and involuntary servitude except as punishment for a crime.
Congress proposed the Fourteenth Amendment on the 13th of June 1866. The Citizenship Clause overruled the Supreme Court decision in Dred Scott v. Sandford from 1857.
Delaware, New Jersey, and Kentucky remained the only Union states that did not ratify it immediately. These three states were exceptions among all other Union members during the ratification process.
Beginning around 1900, former Confederate states passed new constitutions incorporating poll taxes and literacy tests. These laws were administered by white staff with exemptions for whites via grandfather clauses.
The Fifteenth Amendment was ratified on the 3rd of February 1870. Ulysses S. Grant's narrow election victory in 1868 convinced Republicans that protecting black voting rights was essential.