Lucky you: we have enjoyed our times in African countries, and safaris have been highlights. Several suggestions come to mind. Jo'Burg airport is notorious for mishandling/ losing luggage. We were advised to take old, beat up looking bags and were glad we did. A bean bag, or some cushioning for your long lens really helps when taking those great photos as does a waterproof cover for quick protection of the camera between shots. although I am not a gum chewing person, I found it helpful on dusty drives as it seemed to keep my mouth from drying out.
Best wishes for a great trip: safari salama.