im fairly new to growing as well, but i can give u a little advice from the knowledge i have gained.
depending on how much depth your closet has it it hard to tell how many you can fit...
but if you want to maximize space use square pots, ive heard that a pot that holds anywhere from 3 gallons-5 gallons is optimal, but you can start with smaller pots and transplant later. as for soil i have been using scott's seed starter potting soil, it is ideal for germination and clones, contains rooting hormones, and has a good mix for aeration and absorption, plus its cheap and easy to find (walmart, home depot, etc.).
as for ferts, most growers don't recommend using any ferts until after you have a seedling growing and then start with a diluted mix and work your way up...im not sure on what works best but you can find that out from someone once the time comes. i would stick with distilled or bottled water for now.
www.northernlightsgrowroom.com has great prices on lights
anyways, i tried to help as much as possible, im no expert so try to find out as much as possible from reading the posts on here, just figured i would give you some basic hints so you can get started and figure the rest as you go
peace out
grow buds and prosper