Although sometime has passed, I was wondering if you still were seeking connections between Caroll Langston and J.C Napier. I may have an answer for you. I noticed that J.C attended Oberlin
College's preparatory department from 1864-66. On Oberlin's list of minority students, directly above J.C Napier's name is the name of Ida Morgan Napier who attended Oberlin from 1877-1878 in the cons. department. The interesting thing is this roster shows that Ida had become Mrs. Arthur Desaline Langston. From your past posted info. an Ida and Arthur are the parents of Carroll Langston. So here we have Caroll Langston possibly being doubly related to J.C Napier. One way there could be a relation is through his mother who was a Napier and the other way is by Caroll's father being related to Nettie Langston. Now how exactly I don't know. I'm wondering if Ida is a younger sister of J.C. I wonder if J.C and Nettie Introduced Ida and Arthur, there is obviously a reason that Caroll has J.C's middle name as his first. Carroll was employed in an impt. position in J.C's bank. It just doesn't seem like they were distant relatives.
Both J.C and Ida Napier's hometown is listed as Nashville.
Upon further reading of the Oberlin list I notice that there were quite a number of Langstons that matriculated at Oberlin. They were all listed as being from D.C.