A week of work with the companion interjections, and it was nearly released with a bug that would have caused about a quarter of them to go always-unseen, because on about half of the triggers, I forgot to actually assign them their identifying nodes! I had meticulously catalogued the nodes and coordinated seven dialogue files that referred to them, and some of the triggers themselves (mostly the ones I had done first, before I got into the habit) weren't using them. I fixed them, and while testing I also found another error that prevented some of the bard's location-specific dialogue to show up, due to my having written an erroneous area tag in my documentation. I checked the area's actual tag, and corrected the documentation, and fixed the actual dialogue reference.
A few times when I've gone back to older areas to fix a little bug here or there I find things that I did wrong or unnecessarily, or in some cases where I used prefab elements that did things incorrectly. I believe I've corrected all of the prefab lights that had their shadow intensity set to 1, as well I should have noticed by now in my tests, since I have point lights on all the time for better visuals, unless I'm playing a module that had lights set to a shadow intensity of 1.
Sometimes I find placeables that should have been environmental objects, which is most of them, but especially things such as chandeliers and rugs, which remained as placeables, but had their "walkable" flag set to "true" so that they wouldn't interfere with the walkmesh. In general, I prefer to keep things as placeables only if I think I might want to do something with them via script, or if I want them to block line of sight, or not disappear when you pass the camera behind them, such as for walls.
Anyway, with all that out of the way, I think it's done.