Parallel Lives and Dance of Many
Just like the delayed triggered ability and the activated ability of Mimic Vat, the first two abilities of Dance of Many are linked [CR 607.2c], and so are the first and third abilities. The ruling from Parallel Lives applies.


  607.2c If an object has an activated or triggered ability printed on it that puts one or more objects onto the battlefield and an ability printed on it that refers to objects "put onto the battlefield with [this object]," those abilities are linked. The second can refer only to objects put onto the battlefield as a result of the first.


"The token" in the second and third ability is short for "the token put on the battlefield by Dance of Many", and refers to that which the first ability created [CR 607.1]. Since


  put a token that's a copy of target nontoken creature onto the battlefield.


was replaced with


  put two tokens that's a copy of target nontoken creature onto the battlefield.


that which was created was two tokens, so both tokens get exiled if Dance of the Many leaves the battlefield, and Dance of the Many gets sacrificed if either token leaves the battlefield.