Suggestions by @tajomaru

Lupita Nyong'o

as Nenzima in The Harp

Score: +1

Daniel Kaluuya

as Yangala in The Harp

Score: +1

Lupita Nyong'o

as Makia Marsh in The Expanse

Score: 0

Jasai Chase-Owens

as Filip Nagata in The Expanse

Score: +1

Zawe Ashton

as Neytiri Nagata in The Expanse

Score: +2

Johann Myers

as Toussaint in The Expanse

Score: +1