Something I haven't seen being discussed recently:

In the dream, they're re-casting the lead of Adam's movie. Why?

Possibly because Camilla disappeared; although, if we're applying reality to the (dream) situation, Camilla disappeared during the first night, and the "Castle People" brothers were already on their way to meet with Adam the next day. Granted, The Far Off Roque From Another Place knew she (or some woman) was gone immediately, but Adam seems to know that he's re-casting already before any cryptic Hollywood owl-tied* minions derail his life.

*: I just meant this as, "since Roque has owls on his tie, he's owl-tied", but it sounds fun that way, if you want to play word-games.

The interesting thing about the re-casting in Diane's dream: that OTHER blonde at the party, who kissed Camilla? Adam has to say, "this is the girl." (Leaving aside the fact that Rita's "real" name is Camilla -- the individual he has to pick is the blonde at the party).

So -- re-casting Adam's lead as wish fulfillment: Adam's forced to pick someone else, anyone else, so that Diane can have Camilla.

I think you're right on the money about it being Diane's wish fulfillment. If Adam casts Blonde Camilla as the lead in his movie, but things otherwise unfold the same way, then Adam and Blonde Camilla will become an item instead of Adam and Brunette Camilla, and Blonde Camilla and Brunette Camilla will presumably never hook up either. Both of Diane's competitors smoothly removed from the picture with one little change...