My supposed Acronicta hastulifera caterpillars are growing up. And growing into very convincing A. dactylina caterpillars.
A. hastulifera have frosted hairs (hence the common name “The Frosted Dagger”) which these caterpillars do not have. A. dactylina caterpillars have fluffy orange/brown bands, while A. hastulifera have more diffuse orange and gray hairs. They are trickier to distinguish in early instars (see these posts for pics), but at this point, I’m convinced this species is A. dactylina.
Goes to show just how difficult it is to tell the adults apart, that both Dave and I misidentified the mother moth.