I'm so stupid!! Apparently, besides that one piece of paper, there was another one with a code on it under one of the pillows on the bunks. I thought I checked all of them, but I guess I missed one. All of the bunks did nothing except this single one.

I got the first red suitcase open through sheer guessing. (I was sure of the first two and I guessed the last two digits.) The words they gave about making left and right and using the code I HAVE really misled me. If it hadn't been for that, I probably would have searched more. Whatever, I finally got it and I'm gonna eat some pumpkin pie so my brain won't explode.