I would like to know a good way to keep the cabinet cool and humidity correct.

I have basicly the same cabinet in my dad's room, but our cabinet has to doors that open from the middle.

I was wanting to use your idea since I happen to have the same cabinet, but do I need to buy a 400wHPS that has a hood that is air coolable?

I plan on using it to grow 2 Top44 plants with SCROG method. Sound reasonable?