Daughters of John Singleton Mosby married as follows: May Virginia Mosby married Robert Richard Campbell and had: Pauline Mosby Campbell and John Mosby Campbell and Alexander Spotswood Campbell // Victoria Stuart Mosby married Eugene Watson Coleman and had Beverly Mosby Coleman who became a Rear Admiral and Pauline Mosby Coleman. Beverly married Eleanor Parrish Snyder and they had Charles Parrish Coleman and Victoria Mosby Coleman who married Mr. Fuller. Pauline married J. Davenport Blackwell //Pauline V. Mosby unknown whether she married//Ada C. Mosby unknown whether she married//Of his male children: George Prentiss Mosby died an infant // Beverly Clarke Mosby (male) who died umarried// John Singleton Mosby Jr. 1863-1915 issue unknown//Alfred McLaurine Mosby died infant.
Daughters of William Harrison Mosby, brother of John Singleton Mosby, married as follws: Virginia McLaurine Mosby (daughter by 1st wife Lucy M. Booth) married Edward Callohill Burks, Jr. // Annie Stuart Mosby (daughter by 1st wife Lucy M. Booth) married John Winston Hurt. Of his sons: Sherman Harrison Mosby married 'Nancy' // Alfred D. Mosby IImarried first Mary Booth Quarles and second Elizabeth D. Lee // Haveland 'Hal' Booth Mosby married Virginia Mosby // Robert Quarles Mosby marry Mary Ewart.
You can view the genealogy of John Singleton Mosby and his brother at the John Singleton Mosby Foundation online, but they don't do research for people. They have his ancestors posted back to 1600 as well. If I get a chance, I will post an outline here.