Soy formula is sufficient for calcium - it has all of the required calories, nutrients, fat, etc that a milk based formula has. I have no experience with lactose free cheese, but I suspect that it is the same - lactose is a milk sugar and breaking down the sugar in the milk does not destroy any of the calcium, protein, or other contents...just the sugar. Same with soy yogurts, they are seen as a good replacement for milk yogurts for babies with milk allergy or intolerance, and so would be the same for lactose intolerance as well.
You can buy lactose free milk in the supermarket and use that to cook with - white sauces for over fish or veggies, making custard, home made puddings, etc. Or, you can buy lactose drops, which you add into regular milk and it breaks down the lactose for you, and then use that to cook with. The drops you would probably have to get from a chemist but I know when my mom used them (which was about 15 years ago!) she chose the drops because it was much cheaper, and it was handy to have a bottle of the drops in the house when she ran out of Lactaid on a weekend and couldn't get any.