Well if he has been having milk in the pancakes and not having any reactions, that's a good start.
Usually the milk challenge that is done n the hospital (Both my hospital in England and here in Germany, although maybe in some places it is different) do straight milk (as opposed to other dairy products) for the challenge: offer LO 5mls and see how they are for one hour. Then 10 mls, wait one hour, and so on. Some doctors will do a skin test first if there is concern that there may be a local reaction as well.
So if you have started with milk that is added to foods and Caleb is fine, then I would slowly start trying some milk with him and see how he is. Put 5mls in a syringe and squirt it in like meds and see how he is. We introduced dairy over a month, once we knew DS was okay with it. So, he could have milk and I knew he had outgrown his allergy/intolerance but I didn't want to overload his digestive system with too much of it. So for a while he had bits of cheese every day, then I tried some yogurts, then straight milk - it was a while before I went onto things like cream sauces or heavy cream type products (lots of which there are here in Germany, maybe a regional thing).
In terms of calcium, his formula will have enough calcium for him, even if he stays on it past 12 months. As will soy milk -- LOs this age need 500mg of calcium per day. Which doesn't mean they need to drink a lick of cow's milk....sweet potatoes, oranges, broccoli, oatmeal...all sources of calcium, although it is just much easier to get it from dairy. Soy milk won't have enough fat in it for him, but again you can supplement that with other fats, if you really need to go onto soy milk.
HTH
