Sorry it took so long to come across your message but I hope you see this and that the Gossner's I have information on are related to you. Please let me know if they are.
William F. and Caroline Gossner lived at 2307 Jefferson St. in Phila. at time of 1880 census (June, 1880). They are buried in Glenwood Memorial Gardens, 2321 West Chester Pike, Broomall, PA in the plot owned by my great great grandmother, Ann Hope Hart. William, age 46, died shortly after that census and was interred July 27, 1880. Caroline, at age 42, was interred on Feb. 6, 1888.
Here is 1880 census data: occupationbirth(self) Father Mother William F. 46In storePAPAPA Caroline C.33Keeping House PAHollandHolland Frank R8At SchoolPAPAPA John6At SchoolPAPAPA
Boarding with them was Ida C. Hart, age 15, who was the dtr. of Ann and William Hart, the latter being listed as born in Holland (though all other known records have him born in Germany). So possibly Caroline C. Gossner was related to William Hart.
Philadelphia Directory listings I found for Gossner in that era:
William H., laborer, h. 1221 Fulton Peterlaborer, h.r. 427 Marriott Marytrimmings, h. 839 E. Norris Joseph,potter,h. 839 E. Norris
Charlesbrakeman, h. 2414 Perot Joseph,potter, h. 239 Jefferson