Adeniumgirl, I would leave them in the tray that you have until spring. As Hetty mentions about transplanting when having 4-6 true leaves is what I do, but yours have plenty of growing space between each and could stay in this tray till spring. Try to give them the most sunlight possible (not sure of your climate) and keep w temperatures you stated or higher.
You can give a weak fertilizing at 1/4 strength each time you water. Do not push for growth in foliage at this time. With the seedlings, they can be kept moister than adults. Let top of soil dry and then give a watering. Do those trays have holes in bottom? Definitely need them if they do not.
If as I do having to have my plants inside for winter. Your seedlings will grow, but will take off in the spring and summer when they can be outside in full sun.
Rick
