Personally I would take Duff back.

However on the condition that his family moves into the local Barnsley area,

Problem for Duff, Stendal, Ismael or Hecky is that they would becoming back to a club currently showing little ambition and a squad of players unlikely to be good enough to be challenging for promotion. Unless something really good is going to happen at the club why would any aspiring manager / coach want to end up at Oakwell?