Africa is our favourite continent and we hope to go there soon again -- I've been looking at northern parts this time, perhaps around Morocco - Senegal - Ethiopia route but hopefully I can include some more traditional safari en route as well, perhaps to fly in to Morocco and fly back from somewhere in central.
Sounds like we would get along well with your son for travel plans
I don't know much about Amboseli NP but being next to the Lake Amboseli does sound promising, water is always good. Maasari Mara in Kenya is amazing for sun rises but I wouldn't rank it top on my list for animals -- plenty of various big cats though.
Rwanda absolutely! Amazing place! We did gorilla tracking on Uganda's side but both countries are high on our list. Gorilla tracking is among the best things one can do in Africa, just like walking safaris.
South Luangwa, yes! If you can drop on the Zimbabwe side, consider it. South Luangwa is great for walking safaris, absolute must if you're around. Zebras running around, giraffes looking over the trees at you, love it!
I assume you are leaving Botswana out for a reason. It's a great, premium destination and the delta provides amazing wet vs dry season differences. Chobe NP is also worth visiting there, a driving distance from Victoria Falls and nice variety of both sand and river. Always a safe bet.
Overall I would look into trying to get different type of nature and scenery, both sand and water. That will give you better variety of animals and you may also want to look if particular national park is known for high population of certain animals, for example Chobe was our best elephant destination. Also places that have less tourism will have less people, high season in Kenya and there are tens of vehicles around every major sight -- gets pretty annoying quickly. In Zimbabwe we almost had the park to ourselves. We prefer dry season or just before wet season but the seasons do give you variety and the scenery can be totally different.
One does need to visit Kigali Genocide Memorial but overall there's very little need to stay or visit any of the bigger cities. Focus on nature.
We've typically travelled "on our own", in Namibia we rent a car and drove around ourselves (fancy a flat tire in Etosha?
, always book a car with two spare tires. Usually we've booked the connecting flights between countries ourselves and used agencies for accommodation deals and local transfers. Natural World Safaris (
https://www.naturalworldsafaris.com) and Africa Odyssey (
https://www.africaodyssey.com) have worked great and they've got great web sites and guides to look at even if you don't book anything through them. Most countries have pretty good e-visa services if one is required, some countries like Mozambique are a bit more difficult. Overall travelling around Africa is pretty easy, don't have too tight schedule or connections. Kenya Airways is known for cancellations and delays, I would always have a plan B with them.
What comes to the countries we've noticed to prefer the less developed ones such as Rwanda, Uganda and Malawi. Local people seem to be more sincere there although all places have had amazing staff. Kids there are amazing, one doesn't see that kind of open curiosity in western world any more -- imagine a small kid trying your skin to see why it's so white..
In countries with more developed tourism such as Kenya and Tanzania there's quite a big cap between the tourists and locals, some locals threw stones at our jeep in Kenya that was pretty weird. (We try to avoid too fancy places anyway) We try to be super eco-sensitive around there but for example in Kenya there was worrying amount of trash around.
I hope this gives some idea, happy to answer any questions.