Upvote:2
You won't need a visa to transit South Africa if you remain in the international transit area of the airport.
Timatic, the database which airlines use to verify passenger travel documents, states:
TWOV (Transit Without Visa):
Visa required, except for Passengers transiting through Cape Town (CPT), Durban (DUR), Johannesburg (JNB) or Lanseria (HLA) with a confirmed onward ticket for a flight to a third country. They must stay in the international transit area of the airport and have documents required for the next destination.
You will need a visa to enter Lesotho. If you haven't already gotten the visa, you can obtain an e-visa online at Lesotho's official e-visa web site.