1. Temps should be no more than 10 degrees cooler than when the lights are on. If you room runs at 80 degrees, night time should be about 70 degrees.
2. This should be no problems except when the lights are off. Humidity rises at night as plants transpire- so I kick in ventilation or use a dehumidifier. If you are flowering- high humidity can cause mold in the buds.
3. I believe K.F. is stretchy and will continue growing long into flowering- maybe up to 4 weeks.