Dust and Ashes read from the perspective of the holder means that "each upkeep" would apply to either player, and so whoever is active next would return Job to hand; however, "return to hand" specifies that it returns the card to its owner's hand (otherwise I would think it would be a "take" ability), so while this would trigger on the teammate's turn, it would put contents into the hand of whichever teammate owned Job.
For Ark, It says "after 3 turns," so it should be (in my reading of it) three turns based on the person who controlled the survivor before they were moved. I can see an argument that they are controlled by both players while in the fortress and that may cause wonkiness in the timing, but that's how I ruled it if you asked me at a tournament.
Side note: Don't play decks where both teammates have these offenses. If both teammates have the same character (Job or a Survivor) in play with these fortresses, all copies they have are protected by game rule from moving to the fortress (since that would cause two copies to be controlled by the same player). Also, if teammate A's Noah is hanging out in Ark, that means teammate B cannot throw his Noah down, from the same duplicates rule.
