I have heard that the Tories of the South who never surrendered and chose to stay in the new nation to maintain ownership of their property, land and slaves laid the foundations of the Democratic party.
You're wrong about Tories of the South becoming the Democrats. My family line, father and son, fought in the Revolution, at the Battles of Guilford Courthouse and Kings Mountain, where the Red Coat Major Patrick Ferguson, leading Tory recruits was shot from his saddle, dragged by his horse and victorious Patriots desecrated his body in the aftermath of the battle. /spit
As for Tories becoming Democrats, that doesn't make sense.
My published family history has excerpts of last will and testaments listing names of some slaves and the progeny who they were passed to. My direct line was not wealthy enough to have mansions, but did participate in the Democrat side in the Civil War.