Charles lived at 1747 Kilbourne Pl NW.
Jakob may have been Hans Jakob Efsen, with Jakob being his call name, who was born in Denmark and lived in NJ at one point. Either way Jakob H. Efsen lived at 1741 Kilbourne Pl NW
Robert Rockerhausen (also listed as Robert Rockershausen in public records) lived at 618 Q ST NW and still owned the property at his death, so I’m not sure his connection. He also has a grave in MI: http://bit.ly/XEi3O2