Safari honeymoon while pregnant?

Follow on from question about wedding while pregnant – we had been planning our dream Honeymoon in Africa but will now be roughly 18 weeks pregnant at wedding time. Pending a Doctors OK (still so early!), South Africa looks safe enough with no malaria (in most parts) or Zika, but I’m in particular wondering about comfort level of a) transcontinental flight to Cape Town from Boston, one stop but roughly 10 hours per flight for 18 weeks pregnant b) driving safari at 5 months and c) walking safari comfort level at 5 months

Anyone have any real experience with this? I’d call myself an outdoor enthusiast but like a comfy bed to sleep in at night. Done lots of cabin backcountry trips which is what we have in mind for this. Help!