Air Cleaner is a good idea, as for ventilation I have heard just use a ceiling fan. I stumbled upon all this today on reptile magazine, in a leaf tail article where the writer said he used screen for his leaf tails and raised room humidity to 70%. Then moved to the snake guys, who use the fully vented top racks, with high humidity rooms to have high humidity + better ventilation.
Not sure how much, or if air exchange, short of the opening of the door, 2 3 times a day would be needed, as its alot of air, and the room will be filled with bioactive vivs, and the wall that doesnt have vivs, will have a wall full of plants, IE the entire room will be filled with plants, floor to ceiling every wall.
If committed to this plan, I would obviously seal it 100% every inch. I'd have some sort of ventilation system with forced exhaust. And then a powerful air purifier. What I'd do is run the exhaust for about 5-10 minutes every hour or so to exchange all the air from the room. Then when that turns off, have the air purifier go on and the humidifier. That should help keep the room fresh. Something along those lines...