The German Nassau class battleships are generally classed as Dreadnoughts though they used triple expansion engines and had a designed speed of 19 knots. (They could actually do slightly over 20)
Compared to some of the things that have gone on between tribes in post colonial Africa Jim Crow would seem like a paradise to the victims. As for how the rest of world reacts? Without outright massacres I doubt the world notices.
The three improved Admirals (and they would have a separate class name)should, like Hood be complete and entering service before the Washington conference begins. They would of course be retained but in exchange Tiger and 2 of the retained 13.5" Battleships would be scrapped.