Just manage to tank/kill uber duriel with a perma flame shield-BL build that can also farm pit 75, eternal, it was a team of 3 sorcs with different builds one incinerate one firebolt, some deaths, haven’t attempted alone but I suspect it would have worked with some skills also solo.
Blizz sorc. Only fight him tormented (wish the damn Vas items dropped as readily as Living Steel). Can one phase him ~ 50% of the time. Key with the tormented bosses is understanding which of their attacks add dmg multiplier debuffs… and doing your best to avoid / limit those. Duriel’s are well telegraphed. There are YT vids showing 'em if you don’t want to spend the time to ID them yourself. Happy hunting!
I was a Lvl 87 Blizzard Sorc when I took down my first Tormented Duriel and got my Spark.
Oh, there was also a Barb, a Necro and a Rogue along. My contribution to the fight? I did not die. I thought that, under the circumstances, that was a major accomplishment.
Even at Lvl 100 a Sorc cannot do enough damage to kill a Tormented boss. That is unless you are an incredibly skilled player that never makes a mistake or you make a immune build that has all day to whittle the boss down. Bring your lunch. It is gonna to be a hella’ long fight.
Tbh with blizzard sorc it was fine to kill duriel. At least you have flame shield and teleport to evade the two major attacks of him. With my barb i had no freaking clue on how to avoid them, but was not necessary either as you could just tank until he’s dead 
But i would not want to farm with bliz sorc, too exhausting. Kill him once and thats it.
Just to get resplended spark i would suggest to kill lord zir, was the easiest imho
I was able to defeat Lord Zir and Duriel (level 200), solo, with my Sorc Blizzard build, even to carry a friend at level 76! But it took a lot of time!
I was just there, with Flame Shield and Ice Amor.
For other bosses at level 200, I failed!
If you have perma flame shield you will beat Duriel, it’s just a question of whether you forget to press the flameshield button and how long.
With holy bolts, you can cheese every boss except for the Beast in Ice. Just survive long enough for adds to spawn and GG.
Can I kill Lilith with this build?
I am struggling a lot to kill her for the 4th Resplendent Spark
No, Lilith doesn’t have any adds.
So, no way then 
20 chars
Is now, after their hp is nerfed in today patch 
Lilith has adds, if you don’t skip mechanics she has a few. But realistically you can’t cheese her with the bugged holy bolt, even when it was a thing.