As far as cap 12 goes, they're probably trying to impress on the viewer the feeling of coldness. That is the scene where Roy talks to Chuy in the freezer, so it almost makes sense that it be blue.
It's not like they went through and made white corridors look blue. Overall, I think the reviewer nailed it. The scenes appear to be mostly brightened, which may have had the side effect of bringing out a bluer tone (other than the freezer scene). The unicorn scene looks fantastic!