I love Anastasia. No,I luuuuuurve Anastasia. It's a top name for us (at this point in time with a mythical baby).
I actually think calling her Anastasia wouldn't be too difficult to enforce. Stacy doesn't come out easily. Anna does, but platooning between Anna and Anastasia seems totally do-able.
I swear to God, anyone who says it makes them think of 50 Shades of Gray will get an eye roll from me.
EDITed because I was a bit harsh.