Looking at Bold Systems 4 and LBH, Nola aulacota looks quite similar also ( it has the 'row of dots'). On LBH there is a drawing, but no digital image. On Bold Systems 4, 2 of the 5 digital images of N. aulacota look similar. The specimens are held in the ANIC collection, but all were collected in Tasmania. Perhaps N. aulacota also occurs on the mainland at altitude with ecology similar to Tasmania (i.e the ACT)?
I think the dagger-like spots could just be the tips of the serrations along the 2nd line of N. phaeogramma and N. aulacota (note spelling). But I think N. vernalis has a better match to the forewing sub-costal pattern, as shown in Peter Marriott's photo in Moths of Victoria: Part 2.
I had originally ruled out N. vernalis, but now I agree with you, N. vernalis is a better match for the reason you give and is more likely given the more widespread mainland distribution of the species. It is an interesting and diverse genus.