More panels will provide better coverage, dimming the panels will reduce heat, extend their lifespan, and increase their efficiency. The problem with most lights that fall into the sweet spot of wattage for a 3x3 tent is that they are really designed for a 4x2 space. A light designed for a 4x4 or two lights designed for 4x2 will work great in a 3x3, you will get excellent coverage and you will never have to run them at max power. You can get by with just one of the
hlg lights to start but you will have to be running at higher power than if you had two of them or one of the kingbrite lights I suggested.
No, Im saying keep the mother and clones in the box which would be veg only, 18/6 light cycle. When clones get big enough to flower they would then be moved to the tent which would stay flower only, 12/12 light cycle. The plants would move one way, box to tent. I dont recommend topping in general but as I said before it cant really hurt in you current situation. If you add the tent to the setup I would suggest growing small plants without topping, maybe some light lst once you are more familiar with the strains you are growing and how they will fill out your space as they age.
The box already has a light, why are you recommending the cfls? This also sounds like it would make it too difficult to water or move the plants when needed.