And here's how they turned out.
Lesson 1: Do not decorate cookies when your housemate is up on the roof alone and you are worried about him falling off.
Lesson 2: Don't rush due to not following lesson 1. Wait until you can use racks under ALL the cookies so they ALL come out cute and not a big blobby mess of icing.
Lesson 3: When you think the icing consistency is too thin, don't say "it's good enough" and proceed to get it EVERYWHERE. Red blobby icing only went well with the brain cookies. Having a sheet of maple leaf cookies look like they were decorated via a gruesome murder scene was not all that appetizing.
But they still tasted good.