I dont think a box that big will provide you with too much smoke, but regardless of size, these methods will help you with a closet setup.
I would have vented lights on a seperate system, from out side of the obox, through the lights, back out the box without ever having been inside the box. just put the hot ar exhaust somewhere inconspicuous. Also, have a scrubber inside the box, that is, a fan and a coco scrubber, (there are better ways to clean the air, but they'er a little more expensive at first). Have some SOn Ogro lights HPS+blue to have an even light spectrum. Get a UVB Reptisun lamp to produce UVb light, it makes the little white crystaly hairs called trichomes fill with the THC laden resin. I thnk I'd go with soil if i were you. It's a lot easyire to worry about. If you have CO2 tanks and regulators, for some reason, use them, If you can only get those CO2 cannisters for pellet guns and stuff like that, then get those. They'll provide the 1000-1500 PPM CO2 you should have for in creased yield. You could probably go with some cheap thermometer, and a vacation timer for the 400w or so bulb. Get some good nutes and get some seeds and germinated them. Get a magnifying glass to look at the trichomes up close, that way you don't have to guess when to harvest (done usually when 25-50% of the trichomes have turned from clear to milky, and some to amber. Milky is the best, before its too soon, after its too late. The longer you wait the more it truns to a heave body buzz that might knock you out! some people really like this.
Don't take bad close, don't use crappy nutes, don't let the temps rise. Get a glass jar with a glass or metal tob to cure in, plastic bags no good for curing, just transport when needed. Good luck.