The first African American Seminarian to graduate (as best as we can tell) is Benjamin Franklin Wheeler, Class of 1889.
His Alumni Record of Drew Theological Seminary, 1867-1925 entry:
Wheeler is the first individual listed in this volume as having served in an African Methodist Episcopal Zion Church
The first African American undergraduate to graduate from Drew University is Clarence E. Harrison, Class of 1935.
Some Oak Leaves Yearbook photographs of Clarence E. Harrison:
February 17, 2023 Drew Acorn Article about Clarence E. Harrison: