I am thinking a Shrieking Shack and Hog's Head can be placed in one set of Hogsmid. Additional houses are not needed.
In any case, I am waiting for a set with the Ministry of Magic (like D2C), Gringotts, Knockturn Alley and a Leaky Cauldron (as an addition to the D2C Diagon Alley) and the Battle for Hogwarts (third D2C). It would be amazing and the best year of Harry Potter's history in Lego.