Is washing the hair a prerequisite for lifting ritual impurity, and must the prayers performed without washing the hair along with the body be made up, especially when there is no recollection of repeating that action and no intention to lift ritual impurity in subsequent ritual baths?

As long as you are unsure about whether you omitted washing your hair, especially since you suffer from obsessive-compulsive disorder (OCD), do not pay attention to those doubts. It is the original ruling that women wash their hair when purifying themselves from menstruation, postpartum bleeding, and major ritual impurity (janabah), with the intention of removing the impurity. Fear Allah and turn away from these whispers (waswas); for your ghusl (ritual bath) and prayers are valid, and you are not required to make up any of them.