A few points:
How would they put a value on the rigors of segregation?
Would only the Southern States have to pay?
What about Southerners who moved from the South, would they have to pay?
What about Southerners who didn't support segregation?
It would seem to me that those states which had segregationary laws regarding schools, marriage, miscegenation, economic activity and voting rights would be the most likely to bear liability. That would probably be Southern, but a few northern ones would be included. Individual defendants would be those persons and corporations which overtly took segregationist action against living Plaintiffs.
As for damages, thats up to a jury. I imagine they would be pretty severe.