Do Fiyero and Elphie ever reunite?

Well no. Both of the die they really die. Because the book isn't as much about the friendship of Elphaba and Glinda so having her fake her death and never see anyone one again wouldn't fit the whole picture of the book. So in the book Fiyero and Elphaba really die. It's not faked because in the book Elphaba never seeing Glinda again wouldn't be that big of a deal. In fact the author was a little disapointed to find in the musical she wasn't going to die. Then when he saw how heart renching the fake death was in the Musical he loved it. It was more heart renching then having her and her lover really die.

Umm.... In the book.... He died.

if you watch it on the westend, then yes they do reunite.
elphie goes in a trap door, and is really alive when dorothy chucks the water on her, yet they never tell galinda that she's alive.

i'm currently reading a loin among men and fiyero hasn't shown back up. he is not the scarecrow that was the writers of the play trying to tie it in with the wizard of oz...