The book Clotel is fiction. It's important for historical reasons (it's the first novel written by an African-American) but it wasn't history.
I am interested in finding out the truth about what happened to Thomas Jefferson's children. Eston Hemmings Jefferson is of particular interest to me since he became a professional musician. It seems to me that being a fiddler would've been the best possible profession for a son of Sally Hemmings and Thomas Jefferson.
What was Jefferson's relationship with his children? He had two wives; Sally Hemmings being the half sister (and slave of) his first wife.
This older answer should be of interest.
On the same subject I found this:
Black Fiddlers, a documentary from EMAP and the Heritage
Film Project recently began production. It features the legacies of two
families of fiddlers, connected by blood and by marriage to Jefferson and Hemings.
Research from EMAP Artistic Director David McCormick and music historian
and musician Loren Ludwig indicates that Black fiddlers associated with
Monticello mastered and ranged comfortably through — as no
contemporaneous white musicians did — “high” classical and “low” folk
music traditions for white, Black, and integrated audiences.
Although neglected in standard histories of early American music, the stories of
these Black fiddlers make possible a fresh understanding of how American
musicians assimilated European and African traditions to create
uniquely American music.
https://vpm.org/articles/19773/production-begins-on-black-fiddlers-in-charlottesville