I never made the cookies myself. The lady that baked the cookies was the store owner's mother and she didn's speak a word of English, so we never talked because I don't speak a word of Spanish (other than counting to 100)

. I am pretty sure it was just a typical sugar cookie dough similar to NFSC on here. Pretty thick though.
Designs were freehand, unless I couldn't do something. Then I would use the pinprick method. Copywrighted materials had to use stencils.
Decorated cookies could be frozen, but they came out with a more matte finish than freshly decorated cookies.
I don't know why they think they have to hold their secrets under lock and key. There are really no secrets, becuase everything I learned there, I have seen here on cake central. I've got news for C by D, their "secrets" are out and have been out for a long time.
The one thing that does puzzle me is the icing. I never made it from scratch, so I'm not sure how it was made (premade was also used). I know it had to be a hybrid of buttercream and royal. It dries hard but has a buttercream texture and taste. I think I have seen a recipe on here that uses butter in a form of royal icing. Probably super similar to that.
As for volume, it totally depends on where the store is at, how the store markets the product, and the demand for the product. The cookies are so expensive probably because the owners have to cover their costs, make and profit, and pay franchise fees.