Figured I'd include a spoiler link for Waldo if anyone's tired of looking:

https://floor796.com/#t5l1,459,106

He's in the bathroom stall.

I managed to find him without help - I'm stubborn - but man, did it take me a long time to do it. It didn't help that I was constantly being distracted by some new character grabbing my attention. There's just so much here!