Upload & Sell: Off
It was someone you work with. (not the models or locksmith) If they would have broken into the room and taken stuff, they would have taken the entire bag. It was stolen when you first placed the bag back in the room, and I'd be willing to bet it is the person who had access that day AND who knows camera equipment. They know your workflow and probably knew that you wouldn't open the bag for several days, if not longer. They knew what to grab for max profit and or usability.
Honestly, I suspect the 24 year old.
Start contacting ALL local pawn shops and watch Craigslist. Open a new e-mail under a fake account so you can inquire about for sale stuff you might come across. Don't ask for pics of serial numbers, but ask for detailed pics of all sides of a camera/lenses. Use those to check serial numbers.