Narcissa seems delighted to take on all the planning and decorating and so on, with only a few opinions asked of Corvin for what is needed for a traditional celebration; Corvin pulls a bunch of stuff out of his ass about how his Parselmouth celebration went, and Narcissa works her magic with it. On Harry’s advice, Corvin adds a number of names to the guest list. Mostly high-profile muggle-borns and half-bloods, because they need to keep catering to Corvin’s image of kindness. He knows the Malfoys will disapprove but they can’t actually deny him since it’s technically Corvin’s party. Maybe being forced to interact with people they deem "beneath’ them will help them realize that people are just people, no matter their blood status, but Harry won’t hold out hope for miracles.