I do not personally know the relationship between the races in the North and South during the WBTS. But I do know:
April 9, 1865 my ggf was captured at Ft. Blakeley AL. and sent to Ships Island MS. His beloved wife, "Vin" died April 25, 1865. Left at home with no one to care for them were his 3 children. Ages 5, 3, and 1. Three families of slaves, who could have taken what they wanted from "the big house" and just walked off, stayed and fed the children like they were their own, until my ggf was released at Vicksburg, MS. May 11, 1865 and walked 150 miles home.

I don't know and don't care about what Douglas thought and said, I don't know and don't care what relations were any where else at that time, but I do know that in Harpersville, AL. in April 1865 the relationship between one white family and three black families was strong enough to last for the next 142 years.