"...Most of them would have been Poles, Russians, Ukrainians... from the French foreign legion..."
The foreign legion has about 8.000 men in duty. That means that the rest of the 20.000 would have been regular French soldiers. 12.000 soldiers in a conflict that is not your own under the control of somebody you do not like??! Absolutely not funny. Furthermore I think that the French public would not make any difference between the foreign legion and other french soldiers since they have a very civil society.
"...It will happen in 20-30 years. The number of Germans, who think that former DDR is Middle Germany is already growing..."
Those who think that the former DDR is still middle Germany, usually have an IQ of about +/- 50 and live from welfare near Hoyerswerda. Do you really think, that they will have anything substantical to decide in my country? It is wrong to compare Germany's political situation with the 20ties or 30ties of the last century, since most of my compatriots are much better educated than ever before. We learned the lesson well that blind and unintelligent nationalism leads to decay and destruction. Hitler is not possible in Germany anymore. That is a fact. The "Jutta Steinbach Bullsh**" was no big issue in Germany, since most Germans have absolutely no interest in reclaiming those areas we forfeit after WWII. Political dadaism - nothing more. East Germany was really a nightmare to most Germans in the west, since we lost every form of patriotism a long time ago. Germany mutated into a society were the individum is much more important than the country or the nation. Therefore i.E. to most "Wessis" reunification was complete bullsh**. We had no personal benefits from it. Just a waste of money and time. This is something that is often not understood in other countries who had another socialization than we have. Poles have a completely different viewpoint according to their nation. For most of your fellow citizens (and probably yourself too) it would be important, if Poland would grow spacial. This is different in Germany: Since we would have absolutely no personal benefits in annexing Kaliningrad, it is extremly improbable that we will provoke a dispute over this (for us worthless) piece of land.
"...Most of Russian resources is located in Siberia, which sooner or later will be overtaken by China - near the Russian-Chinese border there live about 3 million people (including already hundreds thousand of Chinese) on the Russian side and about 120 million people on the Chinese side..."
Since Putin and his successors can wink with roundabout 9.000 nuclear warheads, the Chinese will stay inside their own territorium for eating their fortune cookies. Believe me - Putin would nuke them to the Saturn if they step over the border, since those resources are the key to a good future for everybody in Russia. This will be not negotiable.