Congratulations on finally making a life long dream happen! Namibia is a great place to hunt and sight see. If you can swing a few extra days, Windhoek is good for maybe 2 full days of things to do, see and places to eat. If you can, maybe add the extra days at the end to give you time for souvenir shopping.
Those Pelican cases are very nice, but they are also a little on the heavy side when compared to a roller duffel bag. Yes, even though this is a "hard sided and lockable case", your ammo will still need to be put in a separate hard sided and lockable box. This separate ammo box CAN be put inside a piece of your checked luggage BUT, depending on the airline rules you're flying on, they MIGHT have you remove the ammo case from you checked bag and check the locked ammo box separately. IF you decide to lock your regular checked luggage it is supposed to be locked with TSA approved locks - combo or key. Same for the ammo box. IF you don't use TSA locks on your regular checked luggage or the ammo box, you are just about guaranteed to have the locks cut off when you pick-up at your destination.
Your rifle case is SUPPOSED to be locked with NON-TSA operable locks and the ONLY time that case is supposed to be opened is in your presence. You do NOT give the keys/combos to anyone for any reason. It's also a good practice to put an extra set of locks with the same key/combo as the first set with a note attached asking the security people who cut the original locks to use these to re-secure the rifle case. Also doesn't hurt to carry a couple of extra little TSA luggage locks in case those get cut or torn off.
Don't pack ANYTHING valuable in your checked luggage you don't want stolen. Spare scope(s), knives, binos, GPS, etc., can go in your rifle case. DO NOT carry a spare scope in your carryon. It's considered "firearm components" and is likely to be confiscated when you go through security screening.
