Thanks to all who replied!
I think that I am, in fact, open hearted. I work in public school in germany (no, not a teacher again).
You have to be open hearted and open minded to work in such an desolate environment (germany spends only half of the money recommended by UN for the educational sector). But all in all it is fun to work with students and my young colleagues.
My pack is just a bit over 5kg w/o poles and water.
I have some electrolytes in granules. Much lighter and easy to consume. I have a self-made health-pack with the recommended contents. Yes, I have made sealed copies of all important documents.
I rise every workday on 5:15, there will be no problem at all to get up early to prevent the mid days heat.
My wife and son will be home, so no need to do any laundry or dump the perishables out the freezer.
I bring a very lightweight raincape (330gr.) just for security and a fleece-jacket for the air-transport, I don't want to get a cold on the first days. I am used to hot weather and do not sweat a lot, so I will need to rehydrate often. I hope that on my second week there will be a temperature drop to the mid 20s. If you take the forecasts for real.
The only thing I need to buy in Biarritz oder SJPdP are some foldable Poles, I broke mine on one of my last training-hikes.
Thanks again for all of your tips!
Buen Camino!
Roland