Why are Malone's sister and Fuji Syusuke's sister both called Miyoko?

Malone's sister's name is not Miyoko, but Nanako Qian Yue.

Miyoko is Fuji Syusuke's sister in The Prince of Tennis. She is beautiful, but rarely appears in the play. Gentle and considerate, I have to tell Zhou Zhu's fortune before the game, and I also volunteered to take Zhou Zhu to the game. Because my parents were away, I took on most of the tasks of taking care of my two younger brothers.

Nanako Echizen is Ryoma Echizen's cousin in the Japanese anime Prince of Tennis. She is a very gentle person. She went to the scene to cheer for the dragon horse during the dragon horse race, and comforted the dragon horse when he lost Karubin, which made him feel at ease temporarily. She is also very popular with male and female students in college.