Unless they definitely have a plan to reschedule, it would have been a cool time to throw something together but Queen has never been spontaneous.
I remember when Eddie Vedder fell in they just got Neil Young to sing and they did all sorts of tracks not on the original set list.
It could have been a unique gig although I know the Adam fans probably wouldn't have cared as much...
Going by the US/UK tour they could have cobbled together:
Procession
Now I'm Here (Brian on vocals)
Fat Bottomed Girls (Brian or Roger on vocals - they've both done it)
In The Lap Of The Gods Revisited (Brian)
I Want To Break Free (Roger)
A Kind Of Magic (Roger)
Love Of My Life (Brian)
Long Away (Brian)
39 (Brian/Roger)
Days Of Our Lives (Roger)
Bass Solo
Drum Battle
I'm In Love With My Car (Roger)
Say It's Not True (Rog/Brian)
Tenement Funster (Rog)
Under Pressure (Rog/Brian)
Guitar Solo
TYMD (Brian vocals)
I Want It All (Brian)
Hammer To Fall (Brian)
Ga Ga (Rog vocals)
Crazy (Rog vocals)
BO Rap (Freddie tape)
WWRY (B/R vocals)
Champions (B/R/Audience type vocals)