You will want to think about a scrog grow if you want to jam the tent.
Yes negative pressure is a thing and it's a thing you will want. Just open one of the larger holes/windows available at bottom of tent for incomming air and one of the little cable openings at top opposite side. If you can afford the 6" inline fan, that might serve you better going into the future. You'll want a couple 6" clip on fans to move air over the tops of your plants.
Much depends on budget of course, but if you can afford them, check out cob lights such as those available from
www.cobshop.net. I like mine a lot. They are noiseless, low electrical draw, highly efficient, small and easy to move around, low
heat throw and they work very well.