Welcome on board Slappy
I see some very interesting point in what you are saying but I can't imagine these kind of people (scientists, engineers...) travelling solely through Germany. Actually I would imagine them going to Switzerland and may be to France through Switzerland.
Moreover, from what I have read in v2.2 bribery and some means of support (high proficiency is exactly that) will get you in France anyway.
About the Dead Zone, from what I understand, it was carved through military operation and by letting people starve to death or die from sickness. Someone, said that France could be somewhat Totalitarian and I wouldn't be surprised by that. I expect to see several concentration camps (so called refugee camps) around that area. Actually, I wouldn't be surprised to see France relying on forced labor as well.
IMO, the military figures given per cannon are way too small. They are based on peace time numbers while the country would at least rely on partial mobilization. They also overlooked the Gendarmerie, Police and Custom forces.
On the dead zone, one question remains about the populations who had been living there before it was established. For the Dutch, you can expect the worse as that country remain at war with France. It seems that some German units also opposed the french advance but that couldn't have lasted very long. Nevertheless, I would expect the German to have face a better situation than the Dutch. People would have been expelled but with no needless violence, part of them being brought to the "New France", another part leaving the area to other regions of Germany.
After all, you have German speaking people in Belgium and France while the people of Luxembourg are simply German. I doubt that none of them would accept any violent action on German people (of course locally things could be different). Many of them would have family living there and they would care.
Things would be very different for refugees, however. Anyway, as long as people don't know or can say they didn't know... (Watched the movie Fatherland, or read the book, it's interesting on that subject).
You ruled out the idea of territorial conquest. I disagree. France may not look at Germany for strict territorial expension but it could very well hope to form some kind of federation with several Landers (especially the non-catholic ones). Germany still retain several valuable mineral ressources.
Moreover, France would need some kind of safe route to Poland. After all, the Polish community of France is really important (my ex-wife family is still sending present there every year and that is more a rule than anything else to Poles) and among our major politician's names are the Poniatovskis. Among their ancestors you'll find the last king of Poland, and the Marshall Josef Poniatovski (1st Empire). I also just realized that another major french politician family is of major Polish descent (Kosciusco-Morizet). One of their ancestor is Tadeus Kosciuszko (a Polish and American hero from the war of independence and from the Polish uprising of 1794: directed against Russia). With Poland in such terrible situation (and all other contenders virtually gone) I would not be surprised to see the French attempting to create some new Polish states (such as the Duchy of Warsaw). And if you want to add some history to that one of our king had been king of Poland. Actually, in a T2K Poland, France hold many Polish symbols that could be as important as the Black Madona.