You said you didn't remember your math!
Close enough.
I was going to post something similar, but you did it much more comprehensively than I would have. Though, I completely forgot how useless Nine Smashes essentially (especially compared to a gladiator/buccaneer using Pincushion with some agility books under their belt). It was like the Gladiator suddenly became a belligerent drunk, but only for that one attack.
Nine Smashes at least could get the Accuracy compensation elsewhere but ... yeah. Pincushion was just that much better anyway so what was the point? Oh well.
It uses the new formulas, just like Untold 1 did. I don't know the specific modifiers, but they actually made the agility stat even more important than in other games; it now affects both bow and gun damage. I think strength might still have some influence on physical skills, but at the very least, pulling the trigger slightly harder won't magically make your bullets do way more damage.
Interesting. If I had to guess, it'll use AGI for their base Damage value and probably use a (STR+TEC/2)+AGI for the scaling on it for skills. Possibly.