The brake should fully let go when the brake lever is not applied and should not get warm when it is not being used. We would check the brake cable tension to make sure that it is not too tight. If that does not help we would remove the brake cable and check to see if the brake is still rubbing.
We have heard a few reports of the brake squeaking so that does appear to happen sometimes. Unfortunately, we have not determined how to stop the brake from squeaking yet though.