I was able to complete The Troubled Keeper with heroes/henchies as follows, with a little luck, firepower, and a lot of interrupts:
Me: Monk/(prof of your choice): Smiting (10+3+1); Protect (10+3); Divine Favor (8+2)
Skills: Signet of Judgment (elite); Holy Strike; Lightbringer's Gaze; Protective Spirit; Signet of Devotion; Purge Signet; Remove Hex; Aegis
Note: Make sure you click on your Lightbringer title.
Hero N/Mo Minion Master (Master of Whispers or Olias): Death Magic (10+3+1); Soul Reaping (6+2); Protection Prayers (11)
Skills: Aura of the Lich (elite); Animate Bone Minions; Death Nova; Putrid Bile; Taste of Pain; Protective Spirit; Aegis; Shield of Absorption.
Note: I had trouble with my minion master constantly dying, so that is why all the monk skills here (and they really helped).
Hero Rit/(prof of your choice) Spirit build (Razah): Restoration Magic (12+2); Channeling Magic (11+2); Spawning Power (6+2+1).
Skills: Signet of Spirits (elite); Bloodsong; Renewing Surge; Spirit Siphon; Protective was Kaolai; Mend Body and Soul; Spirit Light; Flesh of My Flesh.
Second Hero Rit/(prof of your choice) Spirit variant build (Xandra): Communing (12+2); Spawning Power (12+2+1).
Skills: Signet of Ghostly Might; Shadowsong; Pain; Disenchantment; Anguish; Dissonance; Boon of Creation; Flesh of My Flesh.
Hero Warrior/(prof of your choice) (Koss) with as many interrupts as possible: Axe Mastery (12+3); Tactics (12+3).
Skills: Dismember; Agonizing Chop; Skull Crack; Disrupting Chop; Balanced Stance; Distracting Blow; Critical Chop; Rez Signet.
Hero Ranger/(alt prof of your choice) (Acolyte Jin) also with many interrupts: Beast Mastery (11+3); Wilderness Survival (10+1); Marksmanship (10+3+1).
Skills: Punishing Shot (elite); Distracting Shot; Savage Shot; Winter; Troll Unguent; Disrupting Lunge; Comfort Animal; Charm Animal.
I also took two: Henchies: Kihm and Mhenlo.
I tried many times to solo this quest with heroes and henchies over a 24-hour period (I got maybe 4 hours of sleep), and I got obliterated so many times right away until I used this build. Even with this build, I failed a couple times, because the mobs do not spawn the same every time. A lot of the success of this quest is where you and the Rits are standing. I positioned myself by Keeper Lynssa and didn't move more than a few steps away from her at all times.
I started out by positioning the rits right on the edge of area of affect circle, close to the forgotten keepers that are a little ways down the pathways. They pretty much fought the first and second wave of mobs on the opposite sides (with me and Keeper Lynssa in the middle of the room). If the kills on one side got done before the other side, I would have the idle rit go help the remaining mobs on the other side. As soon as there was a break before the next wave, I made sure the Rits were back in their beginning positions. Whenever a few of Abbadon's servants managed to get past the Rits and came at me and Keeper Lynssa, I would concentrate only on defending her and smiting the enemy that was attacking the keeper and me. I also pinged my attack of those that were attacking me so that my heroes would come help me. If you can do so without losing track of Lynssa's health, try to direct heroes/henchies to the enemy warlocks and seers, as they degenerate yours and Lynssa's health really, really fast. The bowmasters are also a must to kill fast, but remember, Lynssa is ALWAYS your main focus for her survival.
I also had everyone in fight mode except the minion master (I put him on guard).
I am not the most experienced character skill builder, so I'm sure as some of you read this, you will know better how to tweak it to make it better. I'm just glad it worked for me, and I think I'll make it my standard exploring fighting build!
For a picture of the builds, click here: gw002.jpg