Congratulations on your first house. Let the fun begin!
Some recommedations on your smoking lounge. Keep the heating and A/C separate from the rest of the house if at all possible. Use a window A/C and a separate heat source (like one of those unvented wall mounted natural gas heaters).
There are a few reasons for this: If there happens to be a return vent in your smoke room, the smoke ends up throughout the house. Second, most house heating systems really dry out the air. A direct heating source like the kind I mentioned actually puts some moisture into the air. Since it's in your basement, it should be easier to control the temp around 70 degrees.
Buy a good room size humidifier and try to keep your room at 60-65 % RH. That way your humidor/cabinet won't have to work so hard to maintain 70%.
When I built my room I put it over my garage. The contractor put an A/C return in the room so I ended up blocking it off. The service vents still work so the room gets pretty dry in the winter. I compensate with a room humidifier but it really uses a lot of water, so I have to fill it daily and it's a pain in the a$$.
I did build-in a recirculating air system the draws the room air through a charcoal filter and sends it back into the room. I used a bathroom exhaust fan with a variable speed control. I also have one of those hepa-filter room purifiers.
Sometimes I use a window fan to draw the smoke outside.
