Extremely new, and in fact on my first grow but here we go!
1) Depends on the strain. Some of the strains I've chosen can grow 4', but I'm learning with my solstrips they just don't want to stretch!
2) I have a tent 2x4x8, which is the same as the area you are describing. Think the plants all depends on what growing style you will be using. Some of the strains I'm planning on growing would only fit 2 plants in that setup. Big beasts!
3) I use Autopots and each pot is 3.9g, again I want to grow giant plants. Only allowed 4 by law here.
My first plant has been abused badly and 2 of them would be perfect in this setup. I honestly would be worried to see how big she would be if I was good at growing lol.