I will take advantage of the word "dream" in "dream setlist", knowing this would be hardly be a plausible setlist (although all the songs have been played live).
First set (with a somehow vocally functional Paul Di'anno)
1. Invasion
2. Sanctuary
3. Remember Tomorrow
4. Prowler
5. Phantom of the Opera
6. Wrathchild
7. Killers
TRANSITION 8. Transylvania
Second set (with Bruce Dickinson)
9. Murders in the Rue Morgue
10. The Number of the Beast
11. Run To The Hills
12. Revelations
13. The Trooper
14. 22 Acacia Avenue
15. Hallowed Be Thy Name
INTERMISSION
Third set
1. Aces High
2. 2 Minutes to Midnight
3. Infinite Dreams
4. Can I Play With Madness
5. Wasting Love
6. The Evil That Men Do
7. Rime of the Ancient Mariner
8. Powerslave
9. Bring your Daughter To the Slaughter
10. Afraid To Shoot Strangers
11. Fear of the Dark
12. Wasted Years
Encores
13. Sign of the Cross (with Blaze Bayley)
14. Heaven Can Wait (with Blaze Bayley)
Fourth set
1. If Eternity Should Fail
2. Ghost of the Navigator
3. Brave New World
4. Paschendale
5. The Reincarnation of Benjamin Breeg
6. Rainmaker
7. Tears of a Clown
8. Eldorado
9. The Talisman
10. When the Wild Wind Blows
11. The Wicker Man
12. Iron Maiden
Encores
13. Journeyman
14. Running Free (with all three singers)
15. Drifter
And I could die happy.