I gotta go Royalty here. Prince is the pick. That would allow them to address safety by moving one of the current corners if they wished. He is a top flight Cb, which they have needed. Too good a value.
As for trading, the ONLY way I see a trade by Dallas is if one of the top two Qbs falls. If Gabbert or Cam are there, they could get some serious value to trade down with Minny.