Congratulations on your pregnancy. from all the things you are wanting for your birth - your best option for success is an independent midwife.
Most Gynae's in Cape Town don't do waterbirths and not all hospitals allow waterbirths!
You can either do a private midwife, home-waterbirth with the backing of a gynae ( who you only see twice in the pregnancy & if there are complications) at a private or state hospital.
Or
a private midwife at Vincent pallotti hospital in Pinelands with the back up of a gynae (again - you'll only see them twice antenatally and or if there's a complication)
Midwives speciallise in natural/normal births.
The practice of obstetrics is for the care of high risk pregnancies & births.
You can have a look at
www.capemidwives.co.za for a listing of private midwives in Cape town (luckily most of them are in the Southern Suburbs)
I am a doula & student midwife who's had both my children at home with midwives, one a waterbirth.
I cannot overemphasise that you need to explore the difference the right caregiver can make to your birth.
As you mention, the cs rate in the private sector in SA is over 70% - were your caregiver is more likely to be a gynae.
if you want to give yourself the best chance of a natural birth- you are goingto have to put in alot of work to get it in this city.
You have to have a midwife!