How do I unlock specializations for my companions?
Solution 1:
Once you unlock Skyhold, all party members' specializations are also unlocked. But, the game currently doesn't actually add the new skill line to them until they're in your party. Just head to a random camp, grab three people, then use the Change Party option to swap in everyone else as you go. As soon as they load into the world, they'll have their shiny new skill tree ready to go.