Margaretha Johanna Botha

Her mother, Gertruida Elizabeth van Schalkwyk, died on June 23, 1885 and she was married on 14 July 1885, her father and his 2nd wife witnessed the baptisms of her children.

Cornelius Andries Oosthuizen and Christina Johanna Martina Oosthuizen (Heunes) are witnesses at a few baptisms of her children.
Her name is on the probate record of Cornelius Andries Oosthuizen as Margrietha Botha (oorlede) however on the probate record of Christina Johanna Martina Oosthuizen (Heunes), Magritha Johanna Marthina is mentioned as the child of Johannes Hendrik Briel and married to P.C Bezuidenhout.

Her calculated date of birth (according to her civil death notice) is prior to both the marriage's of Christina Johanna Martina Oosthuizen (Heunes)
Marriage
Civil Death Notice