How do I avoid repetitions when combining two sentences with the same subject and verb?
Use 同时 (at the same time) if you just want to state that the two are equally true.


  这首歌在「Website 1」上被称为「Name 1」，同时在「Website 2」上被称为「Name 2」。



Use 反而 (instead) or 而 (and/but) if you want to stress the opposition between the two. 


  这首歌在「Website 1」上被称为「Name 1」，而在「Website 2」上被称为「Name 2」。



You can avoid further repetitions by simplifying the second verb or using a synonym. I think you can also omit the location verb after the second 在: 


  而在 [ Website 1 ] （上）（它）叫 / 是 / 被称 [ Name 2 ]