The South African parents basically did what you did,
Tanya, but the most likely combo is Jo(hanna) plus (E)lize. Or, indeed, plus
Elizabeth.
Afrikaans-speaking parents often feel burdened by their historical duty to name their children after the grandparents, which means that a whole bunch of cousins can end up identically named - so they sometimes like to go the fusion route, ending up with a modern-sounding name while still acknowledging Grandma.
Another example you may be familiar with is the South African actor Charlize
Theron. I'd be willing to bet that she's got a
Charlotte (or
Charlene)
Elizabeth in her ancestry!
All the best