Lusaka is still quite a distance from Victoria Falls; I think they would have used Livingstone Airport, like in TAR 1.
For any team arriving in Buenos Aires after noon on 27 Jun, this is the best itinerary:
LA4941 from Buenos Aires EZE to Sao Paulo, 28/1230-1520
SA223 from Sao Paulo to Johannesburg, 1800-29/0740
SA48 from Johannesburg to Livingstone, 1040-1230
Teams missing the last flight can take this flight 15min behind:
BA6291 from Johannesburg to Livingstone, 1100-1245
Here's a less efficient route departing Buenos Aires earlier, but which will get teams connecting to Livingstone on the same flight:
AR1300 from Buenos Aires EZE to New York JFK, 27/2300-28/0905
SA204 from New York JFK to Johannesburg, 1115-29/0805
And in memory of the Gutsy Grannies:
AR1300 from Buenos Aires EZE to New York JFK, 27/2300-28/0905
AA100 from New York JFK to London LHR, 1800-29/0620
SA235 from London LHR to Johannesburg, 1900-30/0715
SA48 from Johannesburg to Livingstone, 1040-1230
Which arrives 24 hours after the original flight.