When trying to catch Zoroak do Entei, Suisune and Raikou need to be shiny?
They have to be the event Legendary Pokemon(not being distributed anymore), so a regular shiny Raikou, Entei, and Suicune won't work.
To interact with Zoroark you will need either:
They are obtained through a 13th movie event. Normal Raikou, Entei or Suicune will not activate Zoroark's appearance. The Raikou, Entei and Suicune obtained from this event are always shiny.
If you have them, you can go to Lostlorn Forest and encounter Zoroark.
Hope I helped. :)
Yes, and they need to be the event raikou/entei/suicune, which are shiny. You only need one, though.