Happy to report this morning that a stroke of insight I had earlier paid off. The companion script is fixed; the companions now sneak, draw/holster, and self-stim correctly again.
Also seem to have fixed a heretofore unseen issue with non-Caucasian companions that was giving my partner in crime some trouble. No idea if my fix will work for her as well, but that's how these things go.
I want to play-test a bit more; assuming no more problems crop up, the first draft of NCCS will be uploaded in a day or two when the companion plugins are done.