Well, the rulebook describes the aura as armour, and the fireball ignores all armour. So you could argue the aura doesn't work. However, there wouldn't be much point to aura spells if that were the case (and they already have numerous limitations). Plus there's no way I'm time spiralling that last scene to such an extent! It took me ages to do.
If I change the post so the fireballs properly ignore normal armour (Julian's shield will still count for its magical bonus of one), it means Admund takes a total of 6 wounds, Hans 7, and Julian 5. That's not enough to cause a critical on anyone, so should be OK. Is everyone alright with that?
Mortus only has 6 magic points remaining, by the way.