We need to explore the possibility of Gesina not being born in +/- 1718. Once this can be established then the dates of birth/bapt of her children can be looked at - and verification sought. Private User your assistance is vital!
https://www.yumpu.com/nl/document/view/55632201/labuschagne-geslags... have her as the daughter of Jan Harmensz Steenkamp and Jannetje van Eck - married 17 Nov 1739 at the Cape (the marriage doc is attached to her profile). That source has her born on 4 July 1723 - Drakenstein, bapt 4 July 1723. 5 Children Jan Harm, Casper, Frans, Frans and Johanna.
You can see the profiles connected following the link to Elizabeth Besselame Sharon. I cannot do much more this morning as previously explained and hope that drastic changes won't be made until they have been discussed here first. Please.
Mostly the baptisms are not indexed on family search and so a lot of browsing is required.
Later.