The Creepees is an obvious reference to Billy Crystal's favorite Baseball team, The Yankees, Billy Crystal voiced Mike Wazowski and even directed a Yankees movie called 61* (2001).
When Phlegm exits the Snore's room, he is seen with a skateboard with Oozma Kappa logo on it. Which is a reference to Mike's "Scare Games" team name in Monsters University.
The alert code is 4-18. The 4th and 18th letters of the alphabet are D and R, standing for Damaged Room.
In Snore's room, there is a picture of a Apatosaurus, which could be referencing Arlo from The Good Dinosaur.
In Snore's room there is a Mickey Mouse ring stacking toy. Pixar is owned by Disney.