NPC Outfits for Players

Are sets such as the ones of Paris' and Hamlet's outfits liable to fall under this category with their own set pages?

Yeah, sure.

Does the Bonita items Bonita Twin Ribbon, Bonita Plumed Ankle Boots, Bonita Silky Glove, and Bonita Silky Dress considered a set and fall under this category with its own set page?

Yes. They're commonly displayed together as a whole and the boots, gloves and ribbon all mention the dress itself, so I would say it's a set.