Advise Namibia Botswana self driver vacation

Hello everyone, as an "Africa newbie" self-driver (2–3 weeks), I am looking for tips regarding the following potential Namibia/Botswana itinerary (the order of locations is not yet fixed):

• Starting in Windhoek or Kasane/Victoria Falls
• Kwando River / Mudumu (Caprivi Strip)
• Divundu / Mahango & Buffalo (Caprivi Strip)
• Maun and Okavango Delta
• Kasane: Chobe River and Victoria Falls
• Makgadikgadi Salt Pans

(deliberately excluded: Chobe National Park and Moremi Game Reserve due to travel budget)

1. Does anyone have experience with these places in the months of November or April/May? Or are those times generally advised against?
2. Is a 4x4 off-road vehicle and prior driving experience necessary if we plan to do all safaris guided and won't be staying overnight directly inside the parks?
3. Other tips: e.g., experiences with camping in Botswana regarding safety? Should we spend a night in the open bush for the authentic Botswana feeling? Or ideas for other places or alternative itineraries?

Thank you so much for your help!