The (still unfinished) min-kill run I did through the Baldur's Gate series (http://forum.baldursgate.com/discussion/37678/im-not-a-murderer-a-minimal-kill-solo-playthrough)
was one of the most satisfying experiences I've had with those games, and I've been meaning for a while to do a similar playthrough of IWDEE. It's not as poetic as the potential next Lord of Murder trying to avoid killing, but it was still a fun challenge.
Ahead of time, I could think of three big reasons why I thought this run might be easier than that one:
1. A rule change by me: ONLY THE LIVING COUNT. This means that killing undead is A-OK. They're already dead! More importantly, I knew I would rage-quit if I tried to do the Vale of Shadows while getting dry-humped by a hundred skeletons. I planned to play it by ear regarding other "constructs" like golems. Does anyone know what the heck a Tarnished Sentry is? Whatever it is, I didn't count it.
2. Heart of Winter gives a ton of easy kill-free experience.
3. Dimension Door. Some of the most difficult parts of my BG run involved getting stuck in a crowd of enemies. Being able to teleport past them would have been very helpful.
But I thought these would be outweighed by four ways this could be more difficult:
1. IWD is very linear, so there's less flexibility on how to do things.
2. It's also much more combat-based. Intuitively, you would expect more killing to be necessary.
3. There's no experience for using thief skills or learning spells.
4. The huge one is that enemies follow you even when they can't see you. They follow you FOREVER, even into adjacent areas, even weeks later after you've been in Lonelywood. To me, this is the number one most annoying thing about this game compared to BG. It just makes no sense at all, and it drives me nuts.
In the end, this run was clearly easier. Being allowed to kill undead made an enormous difference, and I was never running around trying to scrape together tiny amounts of experience or gold. I'd like to try it without the undead relaxation, but not until someone makes a mod to address the absurd following behavior.
My character is an Elven FMT named Zoran (in honor of Zoran Dragic and the $4,000,000 contract he got for having a brother). His stats are 18/79-19-17-18-3-11. Core rules, no mods, lots of reloads. I'll make a post for each chapter and write them all in the first person, even though I'm not really an Elven FMT (or a Slovenian basketball player).
To summarize, the "living beings" killed by Zoran were Lysan, Albion, Yxunomei, Krilag, Malavon, The Idol, Pomab, and Belhifet