Yes there are way to grow in a confined area- If doing one or two plants you may get away with just a few fans. The exchanging of air is extremely important when growing your own medicine. I did not go to school for horticulture but i have spent alot of time asking questions and answering them as well. You can get lots of information around here but it wont all click until you start growing, make mistakes and correct them. The first few grows are usually a struggle- this is normal. You ask someone what may have happened, you get an answer- and you make sure to not do it again. An adult sized plant? This is a wide range, a plant is considered adult after showing signs of sexual maturity. The light cycle controls when you flower and when you veg- theoretically you can have a plant growing forever under 18/6 light. 18 on and 6 off. Some growers prefer smaller number large plants and others prefer larger numbers of small plants (research: sea of green). In a small area such as a small closet you may think about scrogging- this is basically using a net to train the plant to utilize all growing space provided by the light. You will soon realize there is quiet an investment involved to grow the good stuff. It pays off within the first good harvest.
Certain strains produce more odors than others. Some will go unnoticeable others will stink the whole block up. Most of the time this is in the last weeks anyway, a carbon filter can always be installed.
Thanks doc, you check out a few pages back?