Well, I can only find 3 hidden Mickeys today! That is the most beautiful picture of the mansion I have ever seen but I don't see much circular in there!
How long after you began playing did you start receiving your codes? I have been playing since the day after Thanksgiving and I have not received any codes yet.
ETA: Ok, I found them all: Mickey 4, Mickey 6, Donald 1, Goofy 5!