The 13th Amendment abolished slavery. The 14th Amendment stated that everybody (including African-Americans) who was born in the United States is American.
The Radical Republicans called themselves radicals because of a complete permanent eradication of slavery. Freedman's Savings Bank was a private corporation chartered by the government for the economic development of African-Americans.
Andrew Johnson replaced Abraham Lincoln after his assassination, but he was impeached to be impeached, and he was impeached for high crimes and misdemeanors.