, it came to my attention that there may actually be a workaround to get the Bhaalist armor without ever having to murder Valeria.
As it turns out, I still have a bunch of old saves in my original Balanced playthrough prior to me going full time honor mode, so I was able to test it and...he's actually correct. You can steal the Bhaalist armor along with the other items the Bhaalist vendor normally sells just by triggering the ghost to appear during your conversation with Sarevok and then pickpocketing the ghost. . It's a target of 16 sleight of hand skill check in this context (level 12 rogue, 20 dex, gloves of thievery). As per the post I've now included in my edit, the underlying DC check is actually 29.
So, at least in principle, there is now, definitively, a way to get the Bhaalist armor without having to be evil at all. You just have to trigger the appearance of the ghost in front of Sarevok with the "I'm ready to be judged" option (which also doesn't spark disapproval from anyone) and then bring in someone from outside the conversation to pickpocket the ghost that shows up.
Now, the downside: if you fail the pickpocket check here, combat automatically triggers with everyone temporarily hostile. As such, I'm not sure how viable this is for honor mode as that's a pretty high check. But I know you people get pretty creative with this stuff, so the fact that it's at least possible in principle seems like a promising start.
If anyone has any ideas on how to make this process go more smoothly I can test it out on this save I now have. The above was a very lazy potion of invis + pickpocket with Astarion out of conversation (I held him back and then just switched to him during the conversation).
Tagging and for credit and due to common interest in the subject.
edit: . As far as I can tell, it would be pretty easy to make this check automatic. So unless I'm missing something or this is patched, this is a completely viable way to now get the Bhaalist armor on a good playthrough.
edit 2: if someone is able to pull this off in honor mode I'd appreciate you letting us know!