When he strides through a District restaurant, he seems from another era, wearing the same kind of hat once worn by the 19th-century Frederick Douglass, the escaped slave turned abolitionist, publisher and statesman. Douglas is a Douglass reenactor, you see. In a life of performance art, he poses as the great man. Douglas, 60, makes appearances around the country in top hat and tails, orating in the high English and deep baritone for which Douglass was known. His wife, B.J., a singer, often performs with him, portraying the abolitionist’s first wife, Anna Murray Douglass.