BB: (Luther) translated from Greek to common German for his German Bible.
Just remarking here that as far as the NT is concerned, Luther translated from the Byzantine/Majority Greek Textform collated by the Catholic priest Desiderius Erasmus, who found Jerome's Vulgate in such error that it was not satisfactory for re-translating from it into other Gentile languages. Yet the Erasmian Textus Receptus did include the final verses of Mark, the John 8 story of the woman taken in adultery, and even the 1 John 5:7 comma (Erasmus translated it back from the Vulgate, though it was not in his Greek manuscripts, and reluctantly included it for the sake of getting the text published in a timely fashion). If by occasion Luther chose not to include the uninspired apocryphal books found in the Catholic Bible, so much the better.
Erasmus, not Luther, is counted as the father of the Reformation through his supply of a well-researched Greek text. The Spanish Reina-Valera Bible also came from his work, as did the English Crown-authorized Bible and its Tyndale-sourced predecessors.
“BB: (Luther) translated from Greek to common German for his German Bible.”
It wasn’t common German because there was no such thing. He used court Saxon - a particular dialect known to many princes and court officials. He wrote a Bible in a language to impress the important people of Germany. That’s far from “common German”.
Also, he clearly used previous Catholic translations in his work.