That’s basically what Arlington National Cemetery is. The union government seized the land of Robert E. Lee, and planning for if they couldn’t keep it after the war, decided to turn it into a cemetery to basically make it useless as a farm/estate. Lee’s heirs eventually sued and won the land back, but didn’t have much use for it, so they sold it back to the government.
I think Black English has been a major contributor towards towards mainstreaming “y’all” outside of the South. The rise of black stories being told on television and through film, plus the rise of hip hop/rap as a mainstream genre of music, has helped normalize certain phrases that used to only be associated with either the South or with black vernacular.