Interesting older topic, one that many current JW's would not think of but it is a deep subject. Life after death, being able to "bring" up two faithful men who died thousands of years previously, to be and speak with Jesus!
Third heaven? Nothing like that is mentioned in WT studies today, no questions allowed to be asked anymore, just answer the question as noted in a paragraph- where is thinking going on?
1) three men speaking of things either going to happen to Jesus, as Leolai said so eloquently -- his death.
2) Why bring them "back" to discuss what was already prophesied in scripture?
3) Three men witnessed the "vision" as it was called- you only need two witnesses for anything in bible
4) Did this have anything to do with the law and the prophets- which changed with Jesus? Why would that be an issue that would have to be "seen" by the three watching from a distance- since they asked Jesus to build three tents?
5) And if, as the last comment says- Life after death
Side note- where are you Leolai? Always loved your insights and comments.