A fan providing positive pressure through a HEPA filter is essential to an aseptic environment. The HEPA filter also ensures laminar air flow.
The heater should max out at 50C.
Humidity can be generated from an ultrasonic humidifier. This will require a separate water supply with level monitoring.
A common chiller could be shared with the irrigation system. This can also serve as a dehumidifier.
CO2 open loop controls may be possible. CO2 tanks are currently the best option for controlling levels.