flemeth is also cheeseable by dropping like 20 traps where you know she's going to become targetable
broodmother was a pushover if you had a couple mages with maxed out AoE spells, just kept everyone out of melee, stood on a rock and cast inferno/blizzard/lightining whatever over and over till she called in darkspawn nubs, dispatched them, repeat.
tentacles were mostly a non issue if you were on the rocks, or stayed mobile if you weren't they're pretty much incapable of hitting moving targets due to the fact that they don't move, they just burrow and emerge, by that time, you've moved out of range again.