So I found some keys and decided to try Lillith. I thought maybe I should just make a smiter but then I figured I would try it anyway. I couldn't beat her. The strategy I used to kill clone Diablo couldn't work because prevent monster heal doesn't work on Ubers. And I just couldn't hit her fast enough to outpace her regen.
So I was puzzled as to what to do next she's so darn fast blizzard can damage her but it's totally impractical. Again my merc was totally useless. I couldn't tank her well enough to just hammer her down with spells. At some point I decided to try blaze with lower resist.
There was an area that I had cleared out and I would static her down, then cast blaze then at an opportune time cast lower resist with a wand and then run back and forth teleporting when I got to the end and she just keeps running in a line on the blaze taking damage and gradually but not too gradually she gets worn down. She has to run through doors to get to you so that makes her align with the blaze. I think if you were more agile than me you could do it in several minutes easily. It's hard to keep the right distance from Lilith while you're doing this. I had chugged antidote potions and wore a venom ward and irthas collar so I had -75 poison duration and 95 psn resist but even with that you take a surprising amount of damage. The gear is unimportant just max out plus to skills get enough fcr, frw and plus to max psn resist and obviously shop farm a lower resist wand.