What is the title of the Orisha religious leaders?

If you mean clergy, then they are called Santeros or Olorishas. They are the medium between men and the Orisha, they consult the Orishas via dillogun to help people in need, they are mounted ( possessed) by their ' parent' Orisha as to directly communicate with practitioners, ect. A long time ago, Pata Palo, Ogun Toyo, Oba Tola', and ect, were leaders. Ochanle is a leader. Somehow, its easier to find a follower santero than a Leader Santero.

Some people will argue that Babalawos are ' high priests', but they are men initated into the mysteries of Orunmilla by receiving Ifa, and not Ocha as the Santero/Olorisha has. Although it is possible to make Ocha before making Ifa, and it makes these people highly sought after and potentially very knowledgable/powerful. It is, however, not possible to make Ifa and THEN make Ocha. It's because of this that some people regard Babalawos as ' high priests'.

Although there are no real high priests, if one would have to pick, the Oba/Oriate would take that title. These are Santeros that have undergone vigurous ceremonies, and have memerized ( and understand) all Lucumi Ceremony, and can work the Ita' ( i think they read Ita, I think Italero is another name for the Oriate that does the Ita for the new initiates.... not sure about it though..)