Indeed. I count 18 families 'related to' the House of Black, and if all of those are Noble or Noble and Most Ancient we could quickly round out the list.

Both Rosier and Lestrange show up on that list, so that raises my estimate that Bones thinks Quirrel is one of those classmates instead, but both of them were Death Eaters. Since so much is diverging from canon here, I suspect I should stop trying to predict based on canon and just wait to see what's changed.

(I couldn't resist, some more research: the Peverell family is extinct in the male line, suggesting that they might have been Noble and Most Ancient and the Potters, descended from them in the female line, are just Noble. That would mean that Riddle is just Noble, rather than Noble and Most Ancient, though, but who knows.)