Using card tags is mandatory in the Magic Rulings forum. Please check your private messages to learn how to use them. I've added them for this post.
-MadMage
No, Zur has an attack trigger not an ETB. You will not get a trigger just from creating a copy.
On a separate but related note; you seem to be under the misconception that the Token from Mirror Mockery is put into play attacking. It is not. Regardless though if it was created attacking then it still wouldn't trigger Zur because creatures put into play attacking were never declared as an attacker and "When ~ attacks" trigger on being declared an attacker.
When the token that's a copy of Zur enters the battlefield due to Mirror Mockery, that won't make its triggered ability trigger. Even if the token were to enter the battlefield attacking, it would not be considered to have attacked this way for the purposes of that ability (C.R. 508.4).
Using card tags is mandatory in the Magic Rulings forum. Please check your private messages to learn how to use them. I've added them for this post.
-MadMage
Zur the Enchanter
No, Zur has an attack trigger not an ETB. You will not get a trigger just from creating a copy.
On a separate but related note; you seem to be under the misconception that the Token from Mirror Mockery is put into play attacking. It is not. Regardless though if it was created attacking then it still wouldn't trigger Zur because creatures put into play attacking were never declared as an attacker and "When ~ attacks" trigger on being declared an attacker.