Though i didn't see that battle (cause i died on turn 3

) i would say that iron dragons would have been excellent probably .
1 iron dragon and lots of scs would have been enough likely .
If the iron dragon is placed rearmost and with hold orders he shouldn't die . Hence no routing .
Then one or 2 petrify spammers and a few thugs with moonblades or similiar .
AQs are imho far from invincible .
2-3 ghost riders beat a single AQ unless it has very special gear like robe of invulnerability + charcoil shield .
Then the AQ has no quickness though . Another weakness of the AQ is their rather low strength without a storm .
A single AQ can't cast storm though because it would fatigue her .
A dual AQ , one as SC , one as staff of storm bearer + wrather is far from invincible also . Especially the staff of storm bearing AQ is very vulnerable .
Petrify , blindness or paralyze work wonders .