At the very least, I'd completely strike out any frost spells in their 8 slots. They'd all have Barrier, Dorian would have Revive, Energy Barrage with Fire staves, all their respective Focus powers, any fire spells, and all other offensive magic. Dorian though would be dishing out all the massive fire damage though. That said, Solas ( and possibly me) will have Firestorm to boot. 
Based on what I've got written down for this team so far, I think my best bet would be taking Dorian, Cole, and Vivienne to kill this Ice dragon. That's Storm/Inferno, Non-Elemental, and Inferno. I would take Solas, but I really do like the idea of Cole starting the fight with a series of powerful archery attacks... plus, he can (probably) use Stealth to avoid the dragon's notice long enough to reach downed allies so that they can be revived (I won't be learning the Revive spell).
And actually, that just reminded me of the Resurgence Focus power... if Dorian has that in his Necromancy tree, he's going to be extremely useful in fights like this... maybe his pets are good at drawing aggro even without Taunt?
Unfortunately, this just isn't my Inquisitor's ideal match up. He has Energy Barrage and probably a fire staff, but that's about it. I have no idea how useful the Spirit Blade will be, so he'll probably be casting Barrier for most of the fight... Maybe I will take the Stormbringer passive after all...