I suspect your lights might not function if you disconnect your fans. When we got our tank set up last week, one of the light sockets was bad. I called Pinky, at Red Sea in Texas, and as well as a hood replacement, I got a (kind) lecture on the importance of changing out the fans when they begin to get noisy...she told me if the fans stop working, the entire hood will shut down. She also sent me the instructions for changing out the fans.
It probably is not a good idea to run those lights without fans even if you can. You might be surprised at the amount of heat they generate and would likely be a fire hazard. We have a 96 watt power compact in a light sitting above our FW tank and even with the fan in the fixture running, the metal gets pretty hot to touch and can raise the tank temp (46 Gal) 2-3 degrees over the course of the day. Imagine the heat build up in an enclosed hood!
Perhaps someone can suggest a quieter fan to use if noise is the issue?
Cheryl