To answer all the questions posed at once
1. Not smoke free, but I didn't think it was terribly bad on the nights I went.
2. 21+ only. No exceptions
3. Casual clothes are the norm
4. The first set starts at 8pm. There are 2 pairs of pianists that play a series of 1 hour sets, and then the other pair comes on and plays a 1 hour set. I believe the last set starts at 1, but I could be mistaken on this one.