Hrm so, avaline and carver certainly die fast. Not sure what's up with that.
I found the best way to kill the ogre was to either:
1. not kill any mobs at all until the ogre dies, start killing little hurlocks. Once they're dead, heal through any Grunt (sword and board) damage and survive. It doesn't matter if anyone dies after during the swarm part. You only need to kill like 5 mobs.
or:
2. Kill hurlocks but not grunts. mobs swarm. Kill hurlocks but not grunt. Try to stun ogre every chance you get, mostly just attack him.
I did the first one, and had a swarm and died right as the ogre was at like 1%. Second time, carver died to something and I couldn't use potions because of the global cooldown (frustrating). Might have been able to save him had I just ejected him from combat but whatever. Basically it was just Avaline and my mage (at range) hanging back while avaline chugged potions and I healed when necessary which was way too long for my tastes. I've got this hugeass mana bar I want to spend on healing and I can't even do so because the cooldown is so restrictive. Took like 5 minutes to down the stupid thing, PLINK PLINK PLINK. 2hp, 4hp, 1hp, etc
Timeskip:
somehow even with tons of cunning, the flanking passive, bravery, heroic aura, and the shield wall thing, avaline died really fast to something (probably two 2H enemy abilities in a short span of time) because I literally turned around and she was dead. Oops?
Also it's amusing how Isabella can't die. Carver was literally...CARVING HER (herf derp) and she didn't go below 1HP.
Anyways I had to change tactics around (the tactics menu ****ing blows) but even then it wasn't enough because I had to change my mage from aggressive to ranged, Carver to defensive instead of aggressive, etc.
Anyways Avaline and Carver died pretty quicky and with everything on cooldown (seriously 60s cooldown? what the ****? Specing into it shouldn't heal 20% more, it should reduce the cooldown on Heal instead. Ideally like 30s, especially if you're going to have a GCD on potions) so it was just my mage and Varric. I don't know why they auto assigned skills into creation (I wouldn't have taken the glyphs, I'd want some sort of group heal instead.)
The cool part is I went in going "glyphs? **** I'll never use these" then when avaline and carver died I went WELP and started using them and just kited the enemies around, while Isabella took aggro and tanked Hayder (very well I might add, 50% hp for a while). I basically just ran around the whole room and stopped to do pinning shot on a dude, or throw a flask and keep kiting. Sometimes I'd drop a para glyph, but that tended to be a crapshoot since I needed it to target more than one enemy. Repulsion was great though, because it took up the whole isle so i'd kite around and then have my mage drop it right behind varric, and they'd just stand there while we killed the mobs from range, and did this until they all died.
Then we unloaded on Hayder (about 30% at this point) and he died pretty fast.