There are several facilitators that do the PC's along with staff, and students. The parents are required to be Discovery grads only for any of the PC's. Who may attend are the parents/step parents.
There is no set in stone level for the PC1 seminar. I've heard lower levels often are involved.
Never heard of Joan Davis, and I've been around for over 4 years - but not to Casa, only Cross Creek and Spring Creek. As for the major cleaning - never noticed any difference from when I went on a visit or went to the PC, therapy visits, etc., It was always clean. The food for the seminars was a little different, they served it in those carryout trays since we were on short breaks
Each school holds their own PC1 on campus. The PC2 and 3 are usually in San Diego or St. George.