My goodness. I have never had significant problems in the 23+ trips I have made.
I do my own paperwork for my rifles. No problems.
I usually take one rifle. If your rifle isn’t reliable enough to fire 40 rounds in 10-14 days you need a different rifle. I use common cartridges. Nothing fancy.
An extra scope and extra screws are nice but I have never had to use them. Incidentally the Africans love Leupold.
Two rifles are much more hassle than one primarily because of weight and volume.
Occasionally a bag shows up a day late but the airlines deliver it to you in RSA or Namibia. With airline apps that monitor the status of your bags that isn’t much of an issue.
I always use Patrick Wright for tickets and his staff guides me thru paperwork.