Glad to be of help!
Yeah in your temp range LEDs without additional heating would be suboptimal.
630w cmh fixtures always consist of 2 315w bulbs AFAIK.
Humidity-wise you want it to be in the 70s during veg and roughly around 50-60% during flower to reduce the risk of mold, that being said, I have also grown plants in higher humidity so it’s not impossible. Temp in the tent should be over 20° and under 30° so you should be fine, possibly it will be necessary to recirculate the air in the colder months instead of venting it out.
Regular MH bulbs are popular for vegging due to the blue light that promotes more compact growth compared to the red-heavy HPS but they are a lot less efficient than HPS or CMH with the same wattage