I just uploaded my fight with the dragon to youtube to show how to stand and fight it. Found here: https://www.youtube.com/watch?v=WSjv955zgvA&feature=youtu.be Skip to 33.50 for the actual fight
I don't recommend mind controlling the dragon. In my opinion you're more likely to lose control of the fight because it will no longer focus your tank and go wandering around. It leaves too much too chance when the mind control wears off and it looks for a new target to aggro. Plus you lose control over the position of your main party relative to the tank (ie your casters might eat a breath attack because of shifts in positioning). As long as your tank is out in front, the adragans shouldn't be a problem. Crowns for the Faithful should bump your will significantly over 85 points above their accuracy. All they can do is miss beyond that.
My strategy was fairly simple. 1. Tank furtherest to the North and immediate buffs to deflection. 2. Buff accuracy of my party (including suppress affliction to remove terrified debuff) 3. Summons heading off east to intercept the Xaurips. 4. Debuff chain on dragon until stun-locked. 5. Focused attack on dragon until dead. 6. Mop up remaining mobs.
The tank needs at least 190 deflection to avoid all auto-attacks. Potion of Llengraths displaced image (tank), scroll of defence (any lore character) and Crowns for the Faithful (priest) should get you there in your first round of combat action. Crowns for the faithful also puts your will above graze range of the adragan's mind control attacks. Suppress affliction on the rest of your party and use your priest to cast Devotions for the Faithful and Dire Blessing. This should put the accuracy of your party members in the range of 85-100 depending on class. Use the scalebreaker or rotfinger gloves to immediate debuff the dragon's saving rolls by 15-20 (depending on which you use, or even better use both). By this stage your accuracy should be equal to or greater than the dragon's will and reflex saves. Start stacking debuffs which target these two stats first, and then work your way onto other ones once they are applied. Once you knock the dragon prone, you should have control over it for the rest of the fight. Use petrified to ensure the job gets done.
While my priest is working on accuracy, I use to other party memeber to summon units which I send off east to distract the Xaurips.
Easy enough with sound fundamentals I reckon.