While it's wonderful that you're mostly vegetarian, please keep in mind that felines are obligate carnivores, unlike canines (who are omnivore carnivores). Canines can better digest plant based sources and make use of them if animal sources are scarce or limited. Felines do need meat. The more meat you provide, the healthier and heartier they will be.
That in mind, personally, I would not attempt giving them almond, soy, or other plant based food. Even milk from cows usually isn't recommended for kitties as they give digestive upset since some cats are also lactose intolerant as they grow. The only milk I gave my kittens occasionally 2 years ago was a small amount of raw goat's milk, as it's easily digestible and contains a lot of natural enzymes and fats.
They are 2 grown cats now, so no more milk for them. Their favorite treats are freeze dried meats, btw.