I also was recently in Botswana in late Oct early Nov...best time between dry and rainy season there and would say as other longer the better. The stars were find with a 17 - 40. and would recommend that you find out what kind of vehicle you are going to be in so you can figure out how to shoot with that long lens. Some trucks don't have enough room for a tripod. I say forget the Ipad or any computer too much weight and trouble...buy a Nexto extreme(or something similar...B&H) maybe 750gig and transfer your cards to that. I never had any trouble with that and faster than a computer. Do all your processing at home. See if your guides have inverters for their truck so you can use your AC outlet(many people come from Europe besides North America)and charge everything through your ac adapter.
The hyperdrive ipad is a storage device, but it also can transfer images at the end of the day or during, to an ipad for review. I always go for storage devices where I can buy the HDD separate and avoid unnecessary cost. I also personally prefer a bigger screen, so I just use the ipad for critique / review but appreciate everyone is different. All the permanent camps I have been to have power, would not worry about charging in the field, but would take a spare battery. 1Ds works all day without issue even on safari (so 10 hrs use).
Website links OP provided also seem to have modified land-rover vehicles so one assumes that as it is a (rather expensive) photographic trip that they have support sorted out, but I would check to understand the type in use. I've seen pro clamps being used with wimberley heads (or similar gimbals), but a lot of the time I still prefer a beanbag. In other vehicles I have had to resort to monopod and wimberley which is still better for me than hand-holding, but again everyone has their preference.
Given also it is a photo trip - what do the organizers suggest in terms of equipment? Having done the trip before, I would expect some good advice as to lenses in the vehicle & opportunities back at camp.
Finally, if you know what sort of support will be in place in the vehicles, and you have not tried that combination before it is worthwhile if you can trialling it before the trip. I'm sure they will advise you there, but extra prep on "trips of a lifetime" are always rewarding