Megamart does have the best selection. Edensoy milk is some of the best tasting (especially vanilla). It comes fortified in some varieties. Read labels on everything. If the product is from the US, it will list CONTAINS MILK in bold letters on the bottom of the ingredients. Some poptarts are milk free (cinnamon, strawberry, and apple flavor). Be cautious with chocolate. Milk is in all Cadbury chocolate. Some dark brands are vegan. Megamart also has Soya margarine and "Smart Balance" butterflavored spread on occasion. My advice is to stock up when they have it! Also be careful when buying bread, as many have milk as an ingredient. I haven't found any dairy-free cheese in doha. Is the allergy just cow's milk? Can goat or sheep cheese be used?

The pharmacy in City Center has chewy bears calcium vitamins if you are looking for supplements. Good luck.