A buddy of mine was feeding a "stray" and it became friendly enough to attempt to come in the house. He gently nudge it away from the door and was scratched. Within a few days he lost three toes and a portion of his foot. My ex was feeding a stray and it became friendly. I heard a great commotion on the deck one day and discovered him pinning our older female cat to the deck, clawing her severely and pissing on her. The abscess at the base of her tail was bad by the time we noticed it and got her to the vet. As well, there are several nasty diseases that your cats (?, sorry, didn't read thread completely) can catch from other cats. I vote no on feeding any animal I don't know.