EDIT: Done, 7/7 
Keep in mind, I also did all of these in Legion, multiple times (8/12 classes)
Kruul - Vengeance DH (Less than 15 pulls, the only thing that was wiping me, was the dps check, didn’t have the Chronomatic Anomaly / Sunking trinket for cheat death, otherwise would 1 shot I suppose, kept dying on 4th annihilate). Did with normal SL gear, SL flask, SL rune, SL food. No other consumables (didn’t know for unbridled fury since I did it day 1).
Agatha - 2 shot on fire mage, 5 shot on ele shaman (both severely undertuned, was dying on boulders). Used normal gear and normal consumables. Later on, did like 15 attempts on warrior with normal gear, got overwhelmed too fast, so decided to buy some old gear, and I actually 1 shot it with old gear + crusader. Made it trivial, even easier than fire mage and ele sham I suppose.
Raest - Did with frost mage, under 10 attempts. Easiest of them all. Normal SL gear, SL consumables.
Sigryn - Did with retribution paladin, that I absolutely SUCK AT! So no excuses for ya’ll. Sigryn is really easy. 20 attempts (most of them were figuring spells lol). Normal SL gear, normal SL consumables, and I didn’t even know retris have a slow - would be alot easier to kite the melee guy).
Tugar - Did with WW monk, which I suck at even more at paladin. Done in SL 200 ilvl epics and blues. Severely undertuned by any means, really too easy.
Xylem - Did with Havoc DH. Incredibly hard, hardest of them all. It wasn’t so challenging to overcome the P1 survivability challenge, as it’s 100% skill based, but was really tough to beat the dps check in P2. Had to get old gear, old consumes, and still had alot of heartbreaking low % wipes. Hardest of them all.
Black rook Hold - Quite unforgiving actually. 1 small mistake is a failed attempt since the teammates are made out of tissue paper. Last phase is the hardest though, since the heals crit alot of shamans, and the way that mastery works, meaning I would sometimes heal myself too much and kill the teammates with the explosion.