my dog is fine with my cat, he just gets curious and sniffles
her.
and yes, pls dont give milk. Most cats and dogs are lactose
intolerant.
Bear's suggestion of chicken is good. Alternatively, you can try a
hard boiled egg mashed up finely. Just give 1/2 of an egg should be
fine for a kitten.
but do be aware that the moment you start feeding the kitten
outside your house, it will become a regular visitor.