My point about my grandparents is also that while they strictly adhered to their belief and spoke at meetings to like minded people they did not force their beliefs or go out of their way to offend people.My sigs a quote from Charlie Brooker.
They're obligate carnivore so no you wont find a vegan cat to my knowledge, there was a border collie who lived till 25 on a plant based diet tho, pretty amazing.
I very much enjoyed nut based dishes and other vegetarian foods. I don't suppose that she considered milk a sin though as it was the early and mid last century when soya and coconut milk was a bit thin on the ground.