Does the villains phase occur on every heroes turn? Also if the heroes do not move do they still draw an encounter card?
Villains phase occurs after each hero phase. When activating monsters, remember to only activate villains and those monster types that correspond to the hero whose villain phase it is.
You draw an encounter card whenever
A) you have not explored a new tile OR
B) you have explored a new tile and have drawn a black arrow
Moving has no relevance to drawing an encounter, other than that it is harder to explore if you do not move. You still might explore by already being on an unexplored edge, or by using some ability like the Ranger's exploration perk from the older game, Castle Ravenloft.