I'm putting this into spoiler text. Even then I'm going to be circumspect.
One thing that happens during play of adventure four is that the players begin asking characters in the dream what happened. Once they know something is up, they may start asking certain characters over and over again. Remember, only two people might theoretically know, one in the memory and the Chorus. The character in the memory doesn't want to tell, I've even had him accidentally or subconsciously fulfill exit requirements himself rather than tell. As for the chorus, he's so mad during most of the adventure that he might as well have no memory.
Another thing that characters have tried to do is take the Chorus into houses with them. I make the village react very badly to that, but I do it because I'm too lazy to deal with the chorus in all the scenes, not because it would hurt anything.
Finally, I like to start the characters being fully themselves in the memories and then slowly tell the players that the personalities of the templates are trying to creep in, to show their acclimation to the people involved. Let them play that as they like.
Those are just some random thoughts on adventure logistics. You don't need them to run the adventure, but for me, they are tricks that keep things interesting and smooth.