I would veg the plant for 2 months and top it, so you get a big bushy plant. I would try to fill the closet up with buds, so to speak. If you do not want a whole lot of smoke, then no need.
3.) a pc fan as out take with a cooker carbon filter taped on it (maybe you will need two of them to keep all odour in ?)
and some passiv holes for intake in the bottom of the closed (outake in the top)
4.) one 3 gallon pot with coco (maybe a 1 gallon pot to stat it in)
5.) a nice big yilding Femi auto seed
6.) some easy to use coco Nutriens (A+B and micro/cam/Mag)
7.) check your water surplys web site and see if your tap water is clean and what it contains .. and also what the PH is .. buy some PH up or down accordenly to this (keep a water PH of 6,5)
I guess thats about it ..
atlest how I would do a small cheap stealt grow of one plant in my closed ..
and then just hope to yild +2 OZ evry seccon month
(if space enough .. you could add one more 300W and another PC fan later on and try to grow 2 small autos ? then go for a 6500K CLF so you have one of each)