Elsie, This is a very late reply to your message.I hope that you are still interested in your original inquiry.
The Poisson of whom I am a member were from Les Cayes, in the south.The artist you mentioned was my father, Louverture Poisson.Like you, I am very eager to locate his ancestors. Unfortunately, as a young person in Haiti, I never thought of such important family link. I knew my grandmother very well; she could have easily provided me with such information because she had a wall-picture of my grandfather. I believe that Louverture had 2 half-brothers. So there is room for research.If you get this message, let's talk some more...Edith