30 Attks
4 - Nat 20s
4 - 19s
2 - 18s
Obviously, a meager 30 data points aren't going to tell us anything, but it may be worth pursuing data on this to see if the numbers are skewing for higher-level/story-relevant NPCs, even with Non-Karmic dice.
Maybe, but as you say, 30 data points is nothing. 100 rolls (each value is expected to occur 5+ times) is the bare minimum to say anything approaching conclusive.
I'd be surprised if Larian coded certain enemies to use different rng systems given all the troubles they've had with rng since EA release. But hey, it's Larian, so you never know. If you do record those rolls, I'd be interested in the findings and/or happy to do some stats on them.