It is more or less a 13-hour flight.
As there are no direct flights between South Africa and Tunisia, visitors have to transit via one of the European capitals or through Cairo or Casablanca.

Yes, if I am the holder of a private passport (see consular information),
No, if I am the holder of a diplomatic or special passport and provided the visit is less than thirty days.

No.
As indicated by the "Pasteur Institute" of Tunis no specific vaccinations are required to enter South Africa.
Nevertheless, visitors to certain game reserves must get anti-malaria tablets (available at the sanitary service of Tunis-Carthage Airport).

The Rand (ZAR) denoted by R (exchange rate : US $ 1 = R 10.2)
www.ozforex.com/host/ozforex/historybasic.asp

Midwinter occurs in June and July and midsummer in December and January.
Summers are generally warm to hot ; winters dry and sunny except in Cape Town where the rainy season is during the winter.
Days of sunshine range from 265 days a year in Johannesburg to 197 days in Durban.

Yes.
Throughout the year South African time is GMT + 2 (i.e. local time + 1).

The basic rule of the road is to drive on the left hand side.