That sounds like enough for perhaps 2-3 flowering plants space if you split it in half. Five flowering plants would probably need the entire thing. Heatwise it is going to kill you with the insulated cabinet and I'm not sure a squirrel fan is going to cut it......you are going to need something good to pull the hot air out and something else to bring the fresh air in. Otherwise the space will bake.

Take a look at some folks on here's grow logs.....these plants really explode during flowering. You will NEED space.