Dear Sagebrush, You may like to visit this site: http://www.journals....?journalCode=hr to address your question on the subject of Immortality in Daoism.
Dear SeekerOfHealing, Before the Buddha decided to end his existence on earth, he was asked by his chief retainer Ven. Ananda whether there was anything that was not taught to him. The answer was no. One could check all the suttas and sutras of both traditions for dhamma deviations relating to "MCO and other stuff" and such an exercise will fail. Even in Vispassana, breathing and walking meditations, there is no "MCO and other stuff, nor anything that was unspoken.