Hello Med93, during winter, it is okay to put the younger succulents by your south facing window. I would caution you though about misting them, it may be that aspect of watering that is causing the decline of your young plants. Stomates of succulents are closed during the day, so misting does not really work for them. It is at night when they open up, but still not recommended to do misting at night for your plants indoors, it may just invite rot if the water stays far too long on their leaves. It is a different interaction if they are outdoors. So better do waterning only as needed during the day, to allow the water to drain out well.
Too much water at this time of the year is not good for them. Better to water the soil thoroughly once and leave them alone. They are not that water needy this time since it is colder and they are indoors. It is a different scenario if they are actually grown outdoors where there is more interaction with natural light and air, with more gas exchange occuring at night. But still follow the usual consideration, much less water during the cold season.
Got to understand that apart from the lighting needs, have to balance it out with the amount of water the plants should or should not be receiving depending on the time of the year. Adjust/lessen watering as needed.