All of the plants you mentioned love humidity. Addtionally, humidity will help keep the spider mite infestation down in the dead of winter. Air circulation is also critical. A small household humidifier would work; you just have to keep filling it up. I tried that several years ago and it became a chore to fill it up. Rather than spend a lot of money on a greenhouse humidifier, I ran a garden hose up to and then under my greenhouse wall and attached a soaker hose to it. I bought one of those inexpensive battery operated water timers and set it for 30 minutes, 3 times a day during the daylight hours. It worked better than I could have imagined and I have had very little mite or mealy bug problems since using this method. The humidity stays at 65% or better.

Steve