Those are great photos Just1ce. Thanks for posting them!
I'm in the middle of a similar project in one of my basement rooms, so it's very helpful to see what other people have done. That plastic barrier is a great idea to allow using a drop ceiling. Have you considered making some type of input into the ductwork to allow your fans to exhaust the smoke that makes it above the ceiling? I don't know if that will be necessary for you but thought it might be worth mentioning.
Keep us posted on how things come together, and keep the pictures coming too!