My suggestion (need testing):
DICE: take off the Marauders Map face from the dice (this will reduce the luck in the game). Put on the dice the Brown Face: when you roll the brown face you can move a character of your choice:
- Albus: see rules
- Cat: see rules
- Harry, Hermione, Draco, Ron: work in progress...
MAP: The first player of the game will put the Marauders Map on a empty classroom or ladder. If someone enters the room or ladder where there is the Map, he can collect it for future use. When he use the Map (as rules) he will put the map on another place. ....... need testing.
Have you already done further testing or expanded your ideas? The map idea sounds fun (we immediately removed it at game 1 in favor of mrs Norris, seeing it as a broken option).