sorry to say i don't really know of any work on HP that tackles this specifically; i know i've said in response to an ask before that, purely from observation, it seems neither Rowling nor her publishers really seemed to expect people to lock into things in the way they did and the internet fandom took them a bit by surprise. otherwise i think Hufflepuffs would have been given qualities aside from "those people in the background." certainly by the time of Pottermore or whatever they're working on that, though
