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!
About namesakes: Yōko Ono's name is written 洋子 from Japanese 洋 (yō) meaning "ocean" an 子 (ko) meaning "child". Often is also written in Katakana (ヨーコ).Yōko Yoneda's name is written 容子 from Japanese 容 (yō) meaning "contain; allow; appearance" and 子 (ko) meaning "child".Yoko Isoda's name is written 陽子 from the Japanese 陽 (yō) meaning "sun" and 子 (ko) meaning "child".Yoko Zetterlund's name is mainly written in Katakana (ヨーコ)