My daughter is not lactose intolerant but allergic to the milk protein itself. Therefore we have to eliminate all milk products (milk, butter, margarine and cheese), whey, and casein.
My daughter is not a 'milk' drinker but I use rice milk when cooking or making things like mashed potatoes.
We use Earth Balance spread which is vegan and contains no milk or milk by products. Fleischmans UNSALTED (salted contains milk) margarine is also dairy free but we like the taste of Earth Balance better.
As for breadcrumbs, all commercial crumbs seem to contain dairy. I either crush dairy free crackers (just read the labels) or dry dairy free bread (Nickles Light, Cellone again read the labels). To make them seasoned crumbs I add Mrs. Dash Italian seasonings.
For cheese she eats Tofutti brand mozzarella flavored slices. A lot of the rice milk cheese slices or Veggie slices still contain milk.
She loves soy ice cream and soy ice cream sandwiches.
It takes time in the beginning to read all the labels.
Even some french fries contain milk! (We buy ours from Gordon Food Service (GFS)). But you will find foods that work for you and replacements.
Duncan Hines cake and some brownie mixes typically do not contain milk. There are dairy free chocolate chips by Enjoy Life.
I find that I do not have 'special' recipes for her. I typically adapt using her butter or rice milk etc.
All I can say is read, read, and re-read those labels!
Oh and all bets are off when you go out to eat. YIKES! A milk allergy is impossible to eat out with because you never know where milk products could be lurking. Sometimes it is easier to bring your own meal unless the restaurant is very forthcoming with their allergen lists.
Good luck. I know what a chore it is.