Yes.Ofcorse they can.That is the whole point of keeping the clean. Go to a petshop for them to tell you how to.
Put them in a deep sink and only fill the water up so that it doesn't go above their paws. Use baby soap and rub it everywhere except for their face, then rinse them off and dry them. Also when you...
Anywhere from 2 to 6 weeks. Depending on which kitten shampoo you're using. It will let you know in the directions on the bottle.
You should never give a cat a bath at any age.
I've heard it is usually once a week