Suggestions for ventilation

Ok so this is to be my future growing space and I will be using a 400W HPS light. The closet is in the basement and so is relatively cold and dry.

Temperature
It stays about 18-20 degrees Celsius pretty constantly and may even get a little bit colder. I'm hoping that with a 400W light in there the natural coldness and the heat from the light will balance out.

Ventilation
I also need to think about air circulation and C02 replenishment. A burner is out of the question so a more low tech method is preferable (perhaps yeast+sugar+water or a beer brewing kit?). According to other threads and my research the optimal air circulation for my closet would be 192 cubic feet per minute. How large will a fan of that magnitude be? Will it be noisy. If I replenish the CO2 artificially will a small oscillating fan in the room be enough to prevent stagnation?

Odor
My next concern is smell, which hopefully is taken care of by my choice of strain (BC MANGO) which is supposed to be low odor and not smell like traditional marijuana anyway but I'd still like to keep it to a minimum.

Lastly minimizing the light escaping from the gaps in between the floor and the door and the top of the door frame and door is important so that guests wont be intrigued by the strange light coming from the closet and inspect. Thanks in advance for any help.

you will probally be ok with the heat as long as there is circulation and ventilation. without ventilation it will get too hot and humid..... a very small bathroom exhaust fan (50 cfm) will do since you already have a dry cold enviroment but you need somewhere to vent it to. I would not try and cover up the space under the door and use that as a passive intake. you will also need a small table fan or something blowing directly on the plants. and for the odor.... the exhaust should get rid of most of it....... you could hook up a carbon filter to the exhaust fan, but then you will need a much larger fan than 50 cfm