As to the final paragraph of your question: look at a book published by Prin Univ Press in 2015: "Nietzsche's Jewish Problem" 
ISBN
9780691167558

He actually seems to develop a much more sympathetic approach to the sister than you usually hear; it was her husband who was the rabid anti-Semite - she stepped back from it after his death by the 1890s - also never a member of the Nazi party - and never particularly vocal in her support of it (still, she no doubt jumped at the Hitler visit chance - she was an operator!) she also acknowledged apparently genuinely the place Jewish scholars had had in Nietzsche's belated "discovery" - etc etc -- also of note: the Nazi regime always had to treat Nietzsche very carefully - always wanted to "claim him" of course, but that was made difficult by the copious amount of plainly philo-semitism in his (particularly early) work -  I recall lines in Daybreak to the effect of the Jews "inheriting" the Earth and the sooner the better (I summarize)-   --the planned critical edition of his works (briefly?) underway in the mid-30s had to be quietly shutdown for that reason. -- Heidegger was a member of the board for the critical ed. - would love to know how he stirred to pot on that issue!