Vaccines
Yes it is legal although you should make sure the next owner(s) know so they can give them to the cat.
cat with no shots as a sickness thin no so probably not because it can make the other cat sick but if you mean shots like were they cant hae babies thin it should be fine. P.S IF NO SHOTS AND SICK CAT AND LIVING WITH A healthy CAT KEEP separate
It depends on what type of cat it is
It depends where you get them but if you get them from the pound (and only the participating ones) they are $35 and they also give them shots for free :)
Cats tolerate penicillin, but the dosage varies from that humans take. Please take this animal to the vet -- even if you do get the right dosage of penicillin, and even if the cat isn't allergic, I presume from your question you're not able to suture the wound. Please get a vet invovled in this.
Yes, worms can potentially give a cat diarrhea if the cat ingests them. Worms can cause gastrointestinal issues and lead to symptoms like diarrhea in cats. It is important to regularly deworm cats to prevent such issues.
Give it lots and lots of attention find a way to entertain it and regularly feed it
There are cat vaccines (check with your vet to see the most suitable age).
Unless the milk is from its mother, you should not give it any type of milk that we drink. The cat may get a stomach ache.
For sure Rabies and distemper shots, feline leukemia
Don't give any type of medicine to a cat without your vet's permission.
To stop a cat from scratching furniture, provide scratching posts, trim their nails regularly, use deterrent sprays, and give them toys and attention to redirect their behavior.