Poto
Ancient Mariner
Possibly. But I think it was POTO, since Running Free was on the original STOAST setlist. Also POTO and Hallowed are similar length-wise.
But wasn't Phantom in the setlist in that video with Dave holding the setlist? Does that video exist anymore?
Here is the video. If you pause the video at the right moment you see that Phanom and Hallowed both were in the setlist and Run to the Hills the last song.
The setlist was probably
Moonchild
Can I Play With Madness
The Prisoner
2 Minutes to Midnight
Afraid to Shoot Strangers
The Trooper
The Number of the Beast
Phantom of the Opera
Hallowed Be Thy Name
Wasted Years
Seventh Son of a Seventh Son
The Clairvoyant
Fear of the Dark
Iron Maiden
Aces High
The Evil That Men Do
Run to the Hills
Can I Play With Madness
The Prisoner
2 Minutes to Midnight
Afraid to Shoot Strangers
The Trooper
The Number of the Beast
Phantom of the Opera
Hallowed Be Thy Name
Wasted Years
Seventh Son of a Seventh Son
The Clairvoyant
Fear of the Dark
Iron Maiden
Aces High
The Evil That Men Do
Run to the Hills