Sounds like a good plan to me. Lighting sounds about right. I would try a cool tube or enclosed hood, and use about a 275 CFM fan to cool the light, and a fairly big oscillating fan to cool the veg section and make the plants rustle, and the same for bud section.

What's a heavy duty ballast. I hope you mean digital or electronic.

I think you are being a little unrealistic about 3 sections in a 6' tall space. I would want at least 3' for each section veg and bloom, and store your stuff in the kitchen or something.