Hello iminei, with succulents, some are active summer growers, and some are active winter growers. With the plants that you have Crassula ovata 'Gollum' is actively growing when temps are cooler. But as with all succulents, be careful with watering, when it is cold, less water, bigger intervals in watering, got to make sure media is dry before you water again.
I don't grow the Euphorbia you have, but I have observed my Euphorbias they prefer to be kept warm. So I move them indoors by our south facing window during winter. I water them sparingly, since the light intensity is not the same as with summer, so they are not consuming much. During the hot months, they can drink a lot.
Echeverias like temps in the 65F to 80's range. Lower than that, got to keep them dry. Their leaves stash moisture so well, so it can take longer dry out time. Higher than that to triple digits they just stop any growing and wait it out till temps return to the favorable one they like.
Aeoniums are very active winter growers. These ones I never have problems if it rains or not in my area during late Fall to Spring. They truly love the cooler temps. But as always media has to be very well draining to it is not sitting moist too long.
Sempervivums are alpine succulents that tolerates the cold temps well, but still have to watch out that they do not go soaking wet.
With greenhouse growing, do watch your temps and humidity levels. When enclosed if humidity is high, it might invite fungal rotting. So good air circulation must be provided from time to time. It is different when they are growing outdoors, there is more air and sun interaction, and they do their gas exchange at night so the succulents grow better, but got to keep them drier by night time.
