Anyways,
Your central air may be key in a room with that much power. I would use a window unit as well. You can play with both until you get things set to where they should be. May take some time to get it set correctly but I am sure you will figure it out.
If you need to move some air in that room in and out. I wouldn't be using 4" fans/blowers. I would be using 6 to 8" fans/blowers and some 6 to 8 inch ducting. Maybe even larger but that may be enough to exchange air in the room. You have a load of air to move and quickly with the lights you plan on having. If you can move enough air in and out of the room you may not have to use a dehumidifier. Instead of the ice idea I would get some dry ice block and use that instead as it gives of Co2 in the process.