Honey bunch, name change yes as you are SA born I should think. Gender change? No way, only once you'll have surgeon's SRS letter and one e.g. GP to confirm this.
Self, living in SA but on P.R. I can not even change my name (as it will not match my P.R. document and/or passport).
As for that if you SA citizen you don't even need a letter at all. Just apply for the name change at Dept. of Home affairs. Pretty easy I'm told --- unfortunately not for "aliens" like me.
Axelle