Namibia / Botswana travel schedule...for your critics...

Al right, I can only comment on a part of your trip (16/6 and on)
3 nights in Etosha - great, nothing to say about that, and you booked already, great

19/6 The day we still spend in Etosha, late afternoon we drive to Treesleeper camp (or is Roy’s camp better??? We’d like to do a Bushman activity…)
If you do go to Roy's camp you might want to leave earlier than late afternoon. Especially if you want to do an activity. It's only about 200km from Namutoni gate, but you might want to stop and restock in Tsumeb or Grootfontein, and you don'T want to drive at night in this region, there's too many people on the road. Roy's camp had nice campsite, with a bush kitchen (fridge, stove, and all) ; they were also offering dinner.

20/6 Drive direction east to Rundu or all the way to Popa Falls
If you want to do an activiy at Roy's camp, you definitly need to arrive earlier the day before, or spend an extra night there, because the drive will take you all day if you make it to Popa falls (easily doable, but its still 400kms). I would stop in Rundu for lunch maybe, its a very animated town, very african.

21/6 Popa Falls & Mahango NP
It will take 5 mins to see the falls. You can spend some time in Mahango but the park is very small (your restrained to one road with a sedan car).

22/6 Crossing the Botswana border and travel to Tsodillo Hills & sleep there at the campsites (did I understood good that it’s nowadays no problem to get to Tsodillo by normal sedan car????)
It is nowady possible to get to Tsodillo by normal sedan car... BUT, the last part of the road is very tricky... I've heard the rain were pretyy bad this year, so it might be even harder now (I was there in early January, and the first 40kms were great... but the last 10kms were absoluterly horrible. barely passable with a small car). I would suggest you to sleep in Shakawe and try to find out how are the roads, or join other people with a 4x4...Drotsky's Cabin are around 50kms from Tsodilo, (around an hour because part of it is on gravel) so if it's really bad you can always turn around and come back to the camp.
With a sedan car only the main campsite will be accessible to you. It's not super nice, but it's ok (not a lot of shade :( but you won't be able to get to the more quiet sites without a 4x4). There's an ablution block but when I was there the water pump was broken. So bring LOTS of water, food for you stay, etc. (When there's actually water the whole village use the showers/toilets, so might not be super clean)
This thread is about Tsodilo hills

Oh yeah, there is a ATM in Shakawe, so you don't have to worry about changing money in Namibia. If you do have namibian money left, you can change it in Shakawe at the Shoprite, and I heard also at the Wright's Trading Store... Oh, and there's a Barclays' Bank

23/6 Here we have an extra day build in (or another day at Tsodillo or at Drotsky’s or we already drive to Maun)
Drotsky's was very nice. Word of caution: DON'T drink the tapwater up there !!! It was pefectly fine in Namibia (in the national parks) but in Northern Botswana be carefull!

24/6 Maun...
You can check out Audi Camp or Old Bridge backpacker for cheap self-catering mokoro trips

28/6 Both 28 & 29 will be travel days to go over Ghanzi, Gobabis, Windhoek to Sesriem &
29/6 & Sossusvlei
Don't forget to book for Sesriem Camp!!!

You can see my travel report in this thread for my 5 weeks trip in Botswana and namibia
If you do end-up buying the LP guide for Botswana and Namibia (which I don't recommend as I say in my report for a self-drive trip, check out the comments about the edition that I made.

It is a long time since I travelled in that area and things might have changed, but here are a few comments for what they are worth:

Instead of doing a special trip down to Sesriem at the end of your holiday why do you not carry on to Sesriem at this stage? It would be far less of a detour. Then return to the C14 and continue to Walvis Bay.

"9/6 ..... Afternoon: over the Cape Cross seal colonies to Torra Bay"
Will you have sufficient time for that?

"11/6 Palmwag or Ongongo Falls + game driving out of one of both (someone knows bothplaces??)"
Palmwag is (was?) a Wilderness Safaris resort. I don't know whether non-residents would be taken on game drives. I suggest you google "Palmwag". As far as I know Ongongo is a lovely camp-site, but that is all that it is.

"13/6 Epupa Falls (we’d love to visit a Himba village but only when it’s not a kinda “human zoo” experience….)"
There is (was) a Himba village not more than a few hundred metres from the Epupa camp-ground.

"14/6 Relaxing at Epupa Falls (or this Kunene River Lodge???)"
There is a lodge at the falls, but it is not the Kunene River Lodge. That is near Swartbooisdrift about 8hrs by 4x4 along the river.

"19/6 The day we still spend in Etosha, late afternoon we drive to Treesleeper camp (or is Roy’s camp better??? We’d like to do a Bushman activity…)"
You can visit a Bushman village near Tsodilo Hills.

"20/6 Drive direction east to Rundu or all the way to Popa Falls"
Popa Falls may be too far but I do not know where Treesleeper or Roys are located

"21/6 Popa Falls & Mahango NP"
Popa Falls has a nice camp ground.

re Rudik comment: Roy's camp is about 50kms east of Groonfontein. So it's doable to do Roy's camp-Popa Falls in one day. I don't know where Treesleeper is though

I liked Treesleeper. Don't know Roy's though, so can't compare, sorry. Treesleeper was about 1 1/4hrs drive on a v good gravel rd from Etosha's Von Linquist Gate. This is my 'shortcut' road that I take when heading towards the Caprivi strip. It's a D road, but a good one... and meets up with the B8 further on. Just means you don't have to double back through Tsumeb or Grootfontein if you don't want to. Treesleeper to Rundu is v easy in a day.

The Bushman activity was probably about an 1 1/2 hrs. Was very interesting and they pretty much organised it on the spot for me. There are no lodges/rondavels or anyhting there. You'll need a tent. There is a bathroom, and that's it. Bring all your food etc with you. There's not a lot else to do in the immediate area though.

Sounds like the roads around Tsoldilo must have deteriorated a lot since I was there about this time last yr. Had no probs at all. Check with locals. Nice campsite. It was free. And a nice exhibition. You pay a small, set fee for one of the local men to walk you around the hills and show you some of the paintings and explain some of the history. Keep a careful eye out for snakes. I had a v close call with a puff adder here.