Mafia 72. "Little Green Man" Bar

Does the Cheat steal votes permanently or for one turn?

For one turn.

What does "the policeman is looking for a mutant" mean from a gameplay perspective?

It's a check. It performs a check on the player and receives the result "mutant/not mutant".

Does Isolation = block + protection?

Something like that. An isolated unit cannot perform its action, but no other actions affect it either. Not even checks. It is considered protection.