Dear Debsss
Hi I've just joined this website - mainly to respond to your message thread.
I am a decendant of Charles E Suisted (1810-1860) (b Carl Eberhard Sjostedt) and I can advise you that Charles/Carl had no sister Mary.
I can find a reference to swedish nieces 'Maria Frederika Juliana Sjostedt(1825-1848)'. And her sister 'Adelejid Wilhemina Rosalie Sjostedt (b1832 - ?) is mentioned on Charles' Swedish passport issued in Stockholm 1858 during a trip back to Europe from NZ. But I haven't found any family record of Wilhemina coming to NZ and I've speculated that she may have only travelled from Sweden to England with her uncle - if at all.
Then a swedish cousin 'Maria Sophia Obiljana Sjostedt (b 1824-?)
Of the 15 children in total he & his English/Lincolnshire wife, Mary-Emma, had there was one daughter Mary Ophelia Suisted who died as an infant (1838-1841 Tasmania) and another daughter Mary Emma Campbell (nee Suisted) (1848-1933 NZ) no children.
Sjostedt is a reasonably common name in Scandanavia/North America but to date I haven't come across another Suisted that is not descended from Charles/Carl.
Good luck.