Abraham, Lazarus, and Dives

27 And he said, ‘Then I beg you, father, to send him to my father's house— 28 for I have five brothers—so that he may warn them, lest they also come into this place of torment.’ 29 But Abraham said, ‘They have Moses and the Prophets; let them hear them.’ 30 And he said, ‘No, father Abraham, but if someone goes to them from the dead, they will repent.’ 31 He said to him, ‘If they do not hear Moses and the Prophets, neither will they be convinced if someone should rise from the dead’” (Lk 15:29-31).

In my experience, this is sometimes quoted to rule out the possibility of ghosts and apparitions of the dead. 

i) Since I'm not Roman Catholic, I don't believe that men and women canonized by the church of Rome appear to the living. That's not how I define a "saint".

ii) Jesus is telling a fictional story to make a point (or several points). Although Abraham is a real person who continues to exist in the afterlife, he functions as a fictional character in the story–just like the rich man. So this is a fictional dialogue rather than a heavenly oracle. 

iii) I doubt readers are meant to think Abraham has the authority to send people from heaven to earth, but simply refuses to exercise that authority. Abraham is just one of many saints. 

iv) In the first instance, this is referring to the epistemic situation of Jews. People who have the OT. It doesn't address the epistemic situation of pagans. 

v) V31 is an ironic jibe that foreshadows the Jewish rejection of Jesus. If they disregard the argument from (messianic) prophecy, then they'll disregard the Resurrection. And in fact, that's what often happened.

But even then it's not an absolute or universal claim, but just a generalization. After all, the disciples had to witness the resurrection of Christ to be convinced. Even for the disciples, Moses and the Prophets were not enough to convince them.  

vi) In the parable, the barrier isn't between heaven and earth but heaven and hell (v26).