The library can be a flavorful representation of the subconscious, where dreams originate. Manifest or a similar mechanic can represent pulling objects from the subconscious into reality. Scry or something can represent tapping into the subconscious for knowledge. Perhaps some dream creatures mill instead of doing life point damage. This can convey that the danger posed by the dreamworld is mental instead of physical, but no less real.

I don't think there's any conflict between a library theme and an enchantment theme. We can do both, without either one detracting from the other.

I'm not quite sold on the flavor of flipping. Does it represent real objects and creatures becoming dreams and vice versa?