From left to right:

Hilda Nikl
(son of Maria Galka Scheffler
and cousin of Nephi Hacken);
Gustl Nikl
(Hilda's husband)
Gerlinde Hlavac
(daughter of Hilda and Gustl,
granddaughter of Maria Galka,
cousin of Rüdiger Scheffler and Renate Mandel
and cousin once-removed of Bob, Dick, Joan, Sue, Carolyn Hacken);
Josef (Pepi) Hlavac
(Gerlinde's husband), and
Christian Hlavac
(son of Gerlinde and Pepi Hlavac).