They need to know basic CPR and health issues. They need to understand educational process and the various topics of physical education that are taught to PE teachers in college.
Same as any classroom teacher. A minimum of a bachelor's degree, usually in kinesiology, plus teaching certification in whatever state they are teaching in.
That depends on what state you´re in. In california, you need a single subject teacher´s credential. If you already have a BA in kinesthetics, you can obtain a single subject credential with one...