Do case managers have to be licensed?

Short answer is no, RN Case Managers do not need a separate license from their RN. The most common certification for the specialty is the CCM (certified case manager) which most positions prefer, along with a master’s degree.

No; however, employers may require a certification.

They must have an RN license. Most employers also require obtaining the CCM certification with in 3-5 years of employment.

Yes they sure do.

case managers are usually licensed social workers or therapist, however anybody can be a "case manager". It is not a licensed position.
it depends upon the business that is operating it and I would assume state regulations regarding the position.