I think
Magdalene would work better with
Miriam. You could still call her
Magda. Now with
Anastasia, the feel is different from the more down-to-earth
Miriam, however, if you called her
Anya, it would work.
Re: the pronunciation, right before my youngest was born, I did sort of toy with
Anastasia with the pronunciation your dh prefers. I ruled it out due to being concerned that no one would pronounce it that way and honestly, an-uh-STAY-zhuh reminds me of anesthesia. :-(