They were not necessarily the "well-known" ones, like the three dishes in the ballroom scene of the Haunted Mansion. Some seemed pretty obscure to me...and they were scattered among a wide variety of attractions. The clues indicated that the hidden Mickeys are either in the attraction or somewhere in the queue, with a few being out in the open/easy-access areas. The attractions include Roger Rabbit Car-Toon Spin, Mickey's Movie Bar (the Mickey M&G in Toontown), It's a Small World, Mr. Toad's Wild Ride, Big Thunder, PotC, the train, Space Mtn (queue), Winnie the Pooh, Mater (queue), Sky School (queue), Monsters Inc.
I think the biggest issue is that they aren't necessarily the ones that are clearly deliberately placed Hidden Mickey's. For example, this is one of the clues:
The poster is shown in this entry on the
Steve Barett's Hidden Mickey site, but it's not clear if the answer ("a") is the same one he's featuring (which is described as "middle right") and even he describes it as an "approximate" hidden Mickey. I had honestly expected the answers to be the ones that are clearly correctly proportioned (i.e., the ones that you know the Imagineers deliberately placed). I didn't expect them to all be the easy ones that everyone knows, but I figured they'd be mostly ones that a gust would say, "of course!" once they see it and not "I guess that's it" even after seeing it. It's a fun concept, but I don't know if it'll be really popular (i.e., I didn't see a lot of guests carrying around the quest booklet).