So, as I see some have already started posting possible setlists so why not, here we go. Setlist based on Legacy of the Beast structure in terms of songs lenghts and setlist positsioon and centerpiece songs.
1. Moonchild (I don't think they will use Aces again, other option - Wickerman is out)
2. 2 Minutes to Midnight (haven't played that in last few years, so I guess it can make a return)
3. Phantom of the Opera (classic that has to be played once again, especially on anniversary tour)
4. Wrathchild (shorter song after long song, I don't want to hear it, but enough time has passed since it's last appereance, so it's quite possible)
5. Infinite Dreams (they have played Icarus, they have played CSIT and Alexander, so why not give this song a chance after it was omitted from Maiden England tour, like above mentioned songs were omitted from their most suitable tours)
6. Dance of Death (one of the centerpiece songs of the setlist, lots of theatrics and honestly I would love to hear that one, so maybe more of a wishful thinking than evidence based selection, but you never know)
7. Evil that Men do (again popular song that hasn't been played last couple of years)
8. Rime of the Ancient Mariner (main centerpiece song of the set, lots of pyro, much like Sign of the Cross was, also it seems people are pretty sure of this song featuring on the next tour)
9. Clairvoyant (classic short song after long one, also haven't been played in years, I guess should be easy to relearn and play)
10. Fear of the Dark
11. Number of the Beast
12. Iron Maiden
13. The Trooper (you can't leave this one out)
14. Brave New World (maybe unrealistic choice to play a reunion era song in the encores of 50th anniversary, but why not mix it up with a song from reunion era beginning)
15. Hallowed be thy Name (if it is their last tour, then this should be their last song to be played)
Yeah, that's it, although some songs setlist positsion may be improved here and there but all in all I think it may be quite doable. I can see 7th son of a 7th son (also maybe rumoured?) replacing Dance of Death (although it could be quite heavy in terms of 7th son material then). And I would kill to hear Afraid to Shoot Strangers melody live (maybe it will replace Infinte Dreams ). Also, maybe Sanctuary or Running Free makes a return, but hopefully not. And if it is celebration of 50 years, then some short Blaze era song should and could make an appereance.
But, yeah, all in all I can see something like this happening.