Upload & Sell: Off
This has probably occurred to you since your second post but bullhorn/hospital/6am is not a great combination. Along those lines, be thinking about anything else that could be disruptive to patients and staff. Don't expect them to shut-down the hospital to cater to your needs.
On the other hand, it might be wise to politely request that a facilities person be on hand that morning to help you with any building details, particularly with electrical power if you plan on plugging in those Einsteins. Electrical outlets could be overloaded and breakers tripped, causing you to lose valuable time in front of 100 people. Using battery packs for the lights, if you have them, might be a good option.
Think about safety. Use sturdy stands - C-stands would probably be best in this case and get those things sand-bagged down with some type of warning tape/sign around them. Watch any cords and tape them down if need be. If you don't have liability insurance, you need to get it now or cancel the shoot.
It looks like the lobby has colored lights. It might be cool to try to retain some of that but that will likely complicate the shoot more with more directional lighting and perhaps gelling of the lights.
If prints are somehow going to be made available for the participants, you might want to consider having small flyers made up describing when, where, and how they will be made available, possibly with your business card attached. I would hand those out as they leave so they don't have them in their hands during the shoot. You'll have to judge if all that is appropriate given your arrangement with the hospital.
Will it be important for you or the hospital to collect the names of the participants?