I'm thinking nobody copied anyone to be honest. Not intentionally anyway. Shakespeare did make Romeo and Juliet first, however, the anime/ manga has only existed since 2007. tsubasa manga and anime has existed since 2003-5. so if anyone DID copy it'd have been Romeo x Juliet people. THE MORE YOU KNOWWW lol
Nope, I have a friend who isn't into shipping slash.
It's kinda sad though one time we gave her a whole bunch of sugar and she, being really hyper, said that Harry and Ron (Harry potter) could make a cute couple. I have never let her live it down. She denies it even though I have what she said on tape