How long does someone need to be in the hospital after being shot (gunshot wound in leg, no bones were harmed) and stabbed (stab wound in abdomen, no organs or blood vessels have been injured)?

Depends on details: Every case is different because it depends on what got damaged. There are important things in the legs besides bones. Leg tendons, arteries, veins, and nerves can be badly damaged. In the abdomen, there are also important things. Basically, only the superficial wounds would get one out the hospital quickly... unless it was in a war zone with many new casualties arriving daily.