Too cute! It sounds like your kitten is just trying to play with your daughter. I love that your family saved the little guy. Sometimes when kittens are not raised by a mother cat and littermates, they don't learn that biting too hard is painful and obnoxious. You need to teach this. First, make sure that your daughter stops playing with the cat as soon as the kitten bites too hard or goes after her leg. Game over. Immediately. This teaches the kitten that that type of play ends the game. Prevent it when you can. If this happens when the cat is overly excited, make sure to bring that excitement level down and keep it down. If it happens when your daughter just walks into the room, or is only standing/sitting there, try to distract the cat first. Toss him a treat or a toy before he goes for the legs. Make sure you don't reward the cat for playing too rough, toys and treats only if he doesn't make a move for the legs. Then make sure to have lots of fun where the kitten learns to play nicely. Through toys. Play with toys on sticks or strings. Keep those hands and legs safe while allowing the kitten to play. The kitten learns playing nicely is fun. Find other, positive ways for your daughter to interact with the cat: assorted games, feeding the cat, petting him when he is calm, etc. Play often. This reinforces what the kitten is learning, and will help tire him out. Less energy means less likely to attack. You can also use toys that hold food to feed the kitten. This will utilize more of his energy and help him use his brain and body. Try to remember that this is likely a temporary thing. As the cat grows up, he will play less.