Fab Melo may be the more valuable prospect. Not wild about Ed Davis. Fab Melo with his size, mobility and defensive potential may end up being the better player 3+ years from now.
The Grizzlies front office is high on Ed Davis. They love his per minute production. However, the Grizzlies coaching staff isn't. Ed Davis has barely played since going there. Darrel Arthur is just as good if not better as a backup four. The coaching staff want more size. Someone who can play the center position behind Marc Gasol. Both E.Davis and D.Arthur are too small to do that. So they are overloaded there at PF.
Unfortunately, Fab Melo isn't game ready so I don't think he meets their needs. So, I don't think Memphis moves Ed Davis for this package but I do think somebody else could pry Ed Davis or Darrel Arthur out of there either before the trade deadline or next summer. No point in having both guys there. I think there is a chance for a good deal there. To get one of those guys at a good price.