CB Radio's, VHF Radio and UHF radio are all different type radios.
Important is that you and your travel partners have the same type of radio meaning
CB Radio's, VHF Radio or UHF.
Based on how many of these are in your group already you can select one.
CB RAdios in RSA is license free these days.
Small radio, 15w easy fit.
License
For Radios programed with the ICASA UHF free/open frequencies (446.00625, 446.01875, 446.03125, 446.43750, 446.05625, 446.06875, 446.08125, 446.09500, 463.97500, 464.12500, 464.17500, 464.32500,464.37500) you don't need a licence in RSA, NAM, BOT (I can't talk about the other countries). These are typically the walkie talkies you referred to, but there are UHF mobile radios that can be programmed for these frequencies on low output.
For the ICASA approved VHF frequencies 161.15000, 160.45000, 161.50000, with tone 131.8 and 118.8, also known as ORRA channels/frequencies, gives you the nine licensed frequencies.
You can obtain a license by joining an ORRA affiliated club and they will help you with a VHF license for Namibia and Botswana, by joining 4x4
Community.co.za but you have to apply yourself for a license for Botswana and Namibia (I am doing it myself and get this within a week) or by contacting ICASA directly (but goodluck with this)