Don't count so much on family stories. I have found out in my research and that of others that family stories are only a guideline to start with. I have found so many family stories to have been incorrect and have argued with family members that continue to want to believe them in the face of other proof. I'm not saying that what I found is the right answer (although I do believe the Causey/ and Marsalis Malindas are the same even if Erasmus Marsalis is not 'Ras' father), but the first thing you need to do when facing a big brick wall, is the suspend all of your assumptions, and start from scratch. Doing this has enabled me to get over more brick walls than you can imagine. Finding other sources is also a good idea, but depending on family verbal history as the final word is not a very good research tool and will not get you very far.
Gwen