I think it’s abundantly obvious to anyone looking at this with good faith that the autonomy refers to the targeting of the weapon and the decision to fire the weapon.

If you're arguing about whether some weapon is a WMD after the fact, good faith isn't really something we can count on. The whole point of precise definitions is eliminating subjectivity. Anyway, that definition includes cruise missiles, which can't be WMDs because they're in widespread use. This line of inquiry is dead in the water.

Well, I haven't been able to come up with a good definition and I don't think the criterion you've pointed to is very promising.