Uh. So much wrong here. There are some Polish sounding names in western parts of Germany proper - (Dirk Nowitzki is a modern day example), but they came from Poles who came to work in the Rhineland mines centuries ago, an were considered Aryan by the Nazis as they were basically Germans.
Same as there were many originally French surnames acquired from French protestant refugees who settled in the German protestant north (de Maziere is an illustrious German family of French Huguenot descendants who gave many prominent Nazi generals, including current defense minister in the German government).
Yes. One of the Nazi ideas for the Lebensraum was a Wild East populated by German settlers lording over semi literate Slavic farmhands who were supposed to work on massive farms as in antebellum South. All “surplus” Slavs were to be exterminated or starved to death - this was well under way in occupied Poland. Millions of Slavs perished in Ukraine, Belarus and Russia proper.
Actually this caused such an ideological conundrum for the Nazis due to their stance on the Slav population that the Croats were decreed by Himmler a lost Gothic tribe who’ve acquired a Slavic language and forgotten their Germanic roots, while the Bulgarians were designated an Aryan Avar tribe.