Dorian's going to Greatly Disapprove of anything except a mage alliance in IHW, and if if you do that, you're going to incur huge disapproval from Cassandra, Sera, and Vivienne. It's a question of degree. Those who disapprove of recruitment (or in either case from In Hushed Whispers) do so Greatly. Those who disapprove of disbanding the templars are less fanatical about it.
With the trials off, Greatly Disapproves gets you -20 to approval, Disapproves gets you -5, and Slightly Disapproves gets you -1.
My point about choosing to disband the templars is that the only person who GREATLY DISAPPROVES is Dorian, and you can offset a lot of that by choosing "Corypheus must be stopped" when becoming Inquisitor. Cassandra disapproves, but it isn't a "greatly". So it's more a question of scope.
Recruit Disapproval:
Sera: -20 becomes -40
Solas: -20 becomes -40
Dorian: -20 becomes -40 (offset with +20 Greatly Approve when becoming Inquisitor, and a ridiculous amount of approval from his personal quests)
Cole: -20 becomes -40 (he'll leave Skyhold immediately at -30, so this will prevent you from obtaining the achievement)
Disband Disapproval:
Blackwall: -5 becomes -10 (easy to get back with his personal quests)
Cassandra: -5 becomes -10 (do Guilty Pleasures to gain +20)
Vivienne: -1 becomes -2 (Pfft! Not going to worry about that!)
Dorian: -20 becomes -40 (offset with +20 when becoming Inquisitor and do his personal quests)
Iron Bull: -5 becomes -10 (he isn't going to leave over this)
So yeah, this whole thing is going to hinge on Cole. If he leaves, you're never going to get the Trial of the Lovers achievement, so your best bet is to disband the templars.