Sorry for the delay on your PM. Honestly, here at Baylor, the best person to contact is my dad (Doug_Weaver@baylor.edu
There is an article by Sandy Martin of the University of Georgia on the topic of Black Baptists and World War II. Pretty sure it was published in Baptist History & Heritage.
As far as pacifism and Black Baptists, the three most knowledgable individuals would be Sandy Martin, Andrew Manis (civil rights scholar and Baptist minister), and Paul Dekar (who has written the most on Baptist Pacifism).
Manis' book Southern Civil Religions in Conflict might be helpful. I don't think you'll find a significant pacifist legacy. I know Manis addresses Black Baptist involvement in 20th century wars.
Also, I think you'll find that the Southern Baptist archive in Nashville has a better collection of African-American related materials than ABHS. Pretty sure that SBHLA has all the old NBC journals and ABHS does not.