I believe the reason a tent would make it easier is that you could have a veg and flower tent.
5x5 is a big space, believe it or not for a home grow, you can get some respectable harvest from that paired with a 600, or 1000w.
And for a veg room you could go 3x3 or 4x4, that room looks big enough. Save electricity and $$ vegging with CFL's, then use the hps for flower.
The carbon filter is necessary by the flip, if you do not have a carbon filter, you deft need some exhaust setup as others have said. with the two tents you can run ducting through the tents to the other tent, out to another room, window, attic etc.
Growing for personal use is one thing to get dialed into first. To think you will have quality buds and even enough to turn a great profit is an ok mindset, because in our world, there is always a consumer for any quality. But if you get a couple grows under your belt, youll be able to notice different deficiencies, burn, heat stress, humidity problems, temperature issues, cloning.... and most of all learn to keep your mouth shut to everyone and telling no one you are growing. Only us on RIU lol. Take it small then go up. I don;t think people were trying to discourage you, just help see reality.
For smell issues always go with a higher rated inline fan setup so you can dial it down with something like this....
http://www.amazon.com/Variac-Variable-Transformer-300va-Output/dp/B006NGI8VS/ref=sr_1_1?ie=UTF8&qid=1383068210&sr=8-1&keywords=variac
any of those other controllers out there will not save you electricity and will kill the lifespan of the fan.
Hempy buckets are a viable option because they grow 2-5x more than a soil bucket, and are pretty simple to learn and dial into...and are forgiving for newbies...
https://www.rollitup.org/drain-waste-hydro/546006-world-hempy.html
Look into LST and SOG or Scrog style growing, so you can manage your plants height.
There is much to learn, and all comes with jumping in and doing so, expectations are not to be confused with confidence, be confident that you will learn, and use all that you learn to better your next grow, research all free time and you will learn a lot, Rollitup has huge info if you search properly, and videos and books are the first source to go to, before anything.
Enjoy
FJG