Security issues are the same as in Brazil... hijacking, murder, etc, etc. By taking the necessary precautions you limit the danger but can never bo totally safe. Crime is a big problem... I have visited Rio and would say the problems are about the same.
There are many private schools where your kids will get a very good education but you will have to pay. For 2 kid it could be about R2500 / month. There are a limited number of decent state schools still but... There are international schools too but I know little about them. Contact the Brazilian embassey, they should be able to help.
Cost of living is high but it would seem that if you company is willing to pay for housing, car, etc then you are probably in a senior or much needed position and will therefore be well paid.
Medical aid (medical insurance) is all important and will be about R4000-R5000 a month for 4 of you. Medical assistance (ambulances/private hospitals/etc) are available and the quality of care is very good in the private ones covered by the medical aid you pay for.
Sport is one thing that is still big in South Africa and there are several tennis clubs. Fishing can be done in many locations depending on what type of fishing you do.
Not sure of expat groups but Johannesburg has a very large Portugese speaking community.
With regards to Brazilian community... contact the embassey here or google and see if anything comes up.
Thank you for your reply and all tips you gave me.
You are right, unfortunately the similarities between Brazil and S.A is including security issues... I have some examples on this in my family and close friends circle. My mother who lives in Curitiba ( Paraná capital city) was kidnaped four years ago and a cousin living in São Paulo was victim of the same violence. Where I live in Belo Horizonte my wife was attacked in a traffic light. Luckily the losses in those cases were material stuffs only , further to the trauma left for their entire lifes, which fortunately they are able to deal with.
Even so my and my family life in BH is good not being restricted to gated communities. For sure some precautions has to be followed like car closed windows, avoid dangerous areas, laptop and suitcase in the car trunk and so on ... But as you said there is no guarantee ... nowhere even in US or Europe, I guess.
The effects of this behavior is reflecting in this last generation of wealth / high medium class of Brazilian citizens where since babies they were grow up in gated estates and expensive privates schools . As they never had much contact to poor people they don't have compassion to them. I was horrorified when I saw a teenager saying on a TV interview that poor people for him is much the same as an animal. This why social specialists are now aware to. In fact social and race discrimination may take a lift on the so called violence fear, it is a shame and this make worse the social imbalance in Brazil .
My generation (I am 45 years old ) was fortunately because no matter what class or race you were belong to ( I am japanese brazilian / medium class) we had lessons together in a public school considering at that time the best ones. Now I see how wonderful was this experience for me as human being because I could feel how tough can be a life for my poor black and whites friends to whom a single pencil and rubber may costs a lot of money . On the other hand the wealthy friends , white mostly, won motorcycles in Christimas, but they didn't only show off , they used to share this gift with us. Good time.
Unfortunately my children belong to this generation, my wife and me make our best in order to show them that their lifes can be enriched by accepting people aside from their colour skin, education, religion, poverty or sexual preferences. The key is that we have a lot of learnings with diversity.