I like this name, even with the whole "Yoko broke up the Beatles" association. By the way, from what I can gather, Yoko was not the reason they broke up; they just grew apart artistically and fans used her as the scapegoat.
I love the name Yoko! There are so many nicknames like Koko, Yokie, Kokie, or Yoyo. It's beautiful, hardworking, smart, and the meaning ocean child is just fab! I would name my daughter this!