Oh god... where to begin.
Growing one plant is not 1/2 the cost of growing two plants. Also, you have less than a 50% chance of getting a female plant that will grow the buds you want... So I'd recommend you upgrade your system to do at least 2, if not 4, plants. When growing from seed you just can't put all your hopes into one plant.
Hydroponics requires the constant monitoring of your pH levels. You're looking at, at least, $80 in pH equipment and solutions, if not more for a better meter.
Also, LED is a pretty expensive up front cost and the results are not up to par with HID systems. For $100 you can get a 250w hps system, and that'd be much better for this idea.
Yes, you will need ventilation. 80% of the plant fiber is carbon. It breathes that carbon in from the air, and without fresh air you will have tiny, sick, plants. Doesn't matter how many of them you have... Ventilation is as important as light and nutrients.
There are many nutrient systems available. Botanicare CNS 17 is among the least expensive to purchase. General Hydroponics Micro and Bloom are commonly utilized in the system you proposed in a ratio known as the "lucas formula."
Google is your friend. You need to do much more homework. Everything you need is right here in front of you. Growers here are not for teaching. We are for assisting. If you need to learn then you need to read. Find yourself a book and read the stickies in the new grower section. You figured out how to find this site. Sign up. And post a new thread. I am sure you have it within you to research the basics on your own.
