Does Illusion change to the ability of the shown Pokemon?

Question

Say I switch into a Zoroark and is shown as a Magic Bounce Espeon, while the opponent sets up entry hazards. Would the Magic Bounce ability come into effect, or would the hazards stay to your side of the field.

Answer 1

No, Zoroark does not gain a new ability when Illusion triggers. So in your given scenario, the opponent would be able to set up entry hazards like normal -- and probably ascertain the disguise from that.

Illusion changes nothing except the Pokemon that appears to enter that battle. Besides that, Zoroark is unchanged in its entirety -- but that can be part of the plan!