It was mentioned that M and C were at the hotel but I haven't seen any indication that they drove together.I like this line of thinking but it creates an interesting question in my mind. If C & M leave with BM at 5am Sunday morning why is JP involved in this at all? Is it because BM was trying to set up JP to be a POI with the hotel room and deflect attention from himself? But if so, why leave your mail in the trash placing you in that room?
I think the hotel room was meant for Barry. He would have wanted it to be believable that he had planned to stay in the room. When he suddenly left for home, he turned the room over to JP. Wet towels on the floor and envelopes left behind made it look like he left in a hurry due to a family emergency. Imo