Re: Cat as a pet.
Yes, mother’s milk. Not only that but the mother will teach the kitten how to use the litter and groom. Not sure about shelter adoption feeding - depends on the situation. And if you are adopting from a shelter, it doesn’t really matter - it’s an animal that needs a loving home.
In regards to to which to go for, depends on you. We got ours from someone’s litter as we wanted a kitten and it’s rare to find kittens in a shelter.
I think you need to get over the halal issue because at the end of the day you need to do what’s best for your cat, not your own sensitivities. If it’s really going to be that much of an issue.. don’t get a cat. Meat being halal doesn’t even come into the equation. Cats are very picky, ours would never eat enough home cooked meat to constitute a full diet so if we didn’t feed him actual cat food he’d starve. Not to mention, like you said, they will need supplements and stuff. It’s something I did look into and try out but it didn’t work out. Our cat is a fish lover, his wet pouches are fishy types and we give him ‘complementary’ feed of tuna pouches or a little regular tuna from the tin (this is a real treat, they shouldn’t eat too much). His dry food which is the predominant part of his diet is chicken+fish.
p.s. if you’re living in the west, cat food is probably just about as ‘halal’ as the halal meat you consume given modern farming and butchering practices. Especially when it comes to chicken, there’s practically no difference between halal and non-halal slaughter, I barely eat it now.